Friday, December 13, 2013

In Search of "Hamburg Bier"

"Hamburg Bier" also known as Hambourg Bier and Hambourger Bier was the beer that made the fortune of the Hanseatic League. It became famous and synonymous with beer that was made with hops. Unfortunately, few descriptions about the beer and how it tasted exist, and most historical treatments deal with the beer trade of the Hansa rather than characteristics of the beers themselves.

Over the past year, I've been doing quite a bit of research into the historical background of this "Hamburg Bier" circa 1300-1500's. Here's a summation of my current research efforts.

Seems that there are two distinct elements to it. First it is variously described as a red ale made from barley (and wheat) the is sour and more bitter than other regional German biers.

Later the term is used to cover any type of bier that was sourced from the Hansa, i.e. the name "Hamburg Bier" was effectively a regional catchall, covering some 14 or more different styles of bier being produced.

In this regard the historic record is quite muddied making it near impossible to identify one specific style of bier as being definitively the original Hamburg Bier.

In one way, this is good news insofar that anyone producing bier in the former Hanseatic region can rightly call their bier, "Hamburg Bier" however, they cannot claim that it is the original Rezept and method. More on Method, later.

So as far as I can gather, the Original "Hamburg Bier" had the following characteristics:
:- it was a top fermented bier;
:- it was a red bier - not hell, or dunkel, etc;
:- it has some wheat in it; it is sour-ish;
:- it was transported in wooden barrels;
:- it was relatively strong alcohol-wise, i.e. it was no table bier;
:- it was noticeably bitter;
:- the Rezept was given to the brewer by the Stadt and the brewer had to brew according to the Rezept

So, we're looking at a wood aged, sour, bitter, red ale. In beir flavour and tast we are concerned primarily with three dominant taste sensations and with this bier, perhaps a fourth due to Hamburg's water profile. These are: Sweetness, Bitterness, Sourness, & Saltiness.

The other two taste sensations (if you give it any credence) are Savoury (Umami) and Fattiness (Recent Taste Discoveries) and these may assist us to notice fuller flavour and body; and possibly oiliness, which is considered an undesirable defect in bier.

Now, the contentious issue above is with Saltiness, that is the mineral composition of Hamburg brewing water, but also possible seawater contamination of casks (if any). What is interesting to me is that salty biers are not uncommon or considered especially bad, so using this as a possible profile attribute is something I never thought about before.

Before we get into a possible Rezept, we need to look at methods. It is reported variously that the method of brewing Bier in the Hansa was so different, and superior to existing methods that the bier could not be reproduced, or in modern parlance, "cloned" successfully.

More history, around this time most brewers were brewing with Gruit. This only required a Mash Tun and a Lauter Tun. These were typically made of wood, so it seems, and boiling was not a highly required brewing option unless there were some specific vegetals in the Gruit that needed to be extracted.

So, no Kettle in general. If there was boiling needed to be done, it is surmised that it was either done with hot rocks, which adds smoky, ashy elements to the bier, OR a smaller metal kettle was used and a decoction was boiled and added back.

Historians quite clearly state that hops needed boiling, and that hops were the most likely reason for separating the mash tun and the kettle. I would go even further to say that hops are the reason that the Germans developed decoction mashing.

Still further: because of the large volumes of bier being made in urban environments, decoction mashing made it possible to make more bier in large wooden lauter tuns with kettles made of metal that were smaller in volume than the Mash Tun. This what I believe to be the "magical" method that made Hamburg, "...the brewhouse of the Hansa."

Another factor to consider is that several smaller kettles could be used concurrently to shorten the time to produce table or small bier, while minimising the risk of spoilage of the partygyled grist.

Decoction Mashing involves taking around 10% or so of the mash in a porridge like consistency and boiling it before putting it back into the mash. This often leads to caramelising the decoction somewhat due to burn spots in the kettle as a result of uneven heat distribution throughout the base of the kettle.

This results in bier that tends to have toasted and caramel characteristics, which are complemented by malty full bodied bier styles. So, back to the Rezept.

Red ales, as we know them, are typically a malt forward, well bodied bier with complementary hop flavour if it is present at all. Usually such bier is, "all about the malt." But "Hamburg Bier" was also bitter and sour. Therein lies the rub.

First: Hops. While the Hansa saw a great trade in hops it is reasonable to proceed that the most commonly used hops would have been grown locally or sourced close to the region. today, the most likely candidate for such hops are from Tettnang. It is my conjecture that these would have been the primary hops in used back in the day.

Next: Malt. It is probable that due to the malting methods of the times (floor mating, and fire kilning in particular) that the malt was have been underdeveloped thus would have needed a protein rest. It would also have been slightly smokey. Malt would have been imported from other parts of Germany because the weather in Northern Germany is too unpredictable and cold for consistent and reliable malt production, or so I've been told.

Not being described as a, "Wheat Beer" (Weißbier, Weißen) it is my supposition that "Hamburg Bier" was mostly barley malt, with some wheat (or wheat malt) - to pull some percentages out of the air? Perhaps 10-15% Wheat in the grain bill?

Next, We need base malt plus some "Munich" or "Amber Malt" to bring the red colour up. Hazarding a guess based on trade activities, I would say that Munich Malt would have been the colouring malt OR the local malt was generally darker in colour and naturally tended towards reddishness.

Today, I'd recommend using Pale malt and Caramber malt.

Lastly, maltwise, "Hamburg Bier" was sour. There are four ways to do this:
:- allow the fresh wort to naturally ferment with wild yeasts;
:- dose the fresh wort with sour dough starter;
:- ferment with barm from a previous bier and then inoculate post-primary with a lactose strain;
:- or use Saurmalz.

It is my reckoning that due to production consistency requirements that dosing post-primary with a souring agent would have been the usual method, as we find record of this in later brewing records for the making of "Berliner Weiße."

I also think it is highly plausible that Sauermalz may have alternatively been used. The first two methods would have produced results but I hazard that they would have been to unpredictable for large, reliable, consistent production usage.

With Sauermalz we would possibly want around 1-2% of the grain bill. this would need to be experimented with to get a good balance of sourness against maltiness.

This brings us to yeast. Sour Dough Starter or Top Fermenting Yeast? I think top fermenting yeast would have been known about, and preferred. It is of course possible that sour dough starter may have been used as a souring agent post-primary.

Barrel Aging. Wooden barrels either from oak or from beech were commonly used. The question we need to ask here is whether the barrels were purpose built or recycled from wine use. Thus, were the barrels toasted inside?

Personally, I think they were not given a charring inside and would have been used raw. Apparently, they were purpose built for beer, and thicker than wine barrels, so as to handle the greater pressures in the barrel. The next question that comes then, is if sour bier is left to sour in the barrel, do the bugs which sour the bier stay in the barrel and if so how do you get them out, if at all? Quite probably, and the barrels were often reused because barrels were expensive.

This concludes my current thought process on "Hamburg Bier." Next to come is the development of a test Rezept and then some more tinkering and fathoming on how to produce a more historically accurate rendition of the bier.

NOTE: Be aware that in light of any new information turning up, all of the above could be completely wrong. But then, I'd be happy to be wrong if, in being so, a genuine, original Rezept for "Hamburg Bier" AND an historically accurate Hamburg brewing method, was to surface and be made freely and publicly available to all.

Until next time,

It's Your Shout, Mate!

Monday, June 3, 2013

iCelsius Pro Review for Home Brewers

Great idea, badly executed - next to bloody useless if you ever dreamed of using it with your iPad/iPhone for HACCP Monitoring, or even just monitoring temperatures in your mash.

I was Soooo Happy when I finally received my iCelsius Pro Temperature Probe for my iPad, thinking it was a, "... shame they didn't have one compatible with the iPhone 5 - ah well, need to get a dongle." I won't be doing that, I can tell you right now.

The iCelsius Pro has a 4" stainless Steel probe with shrink wrapped cover and 1 meter black cable. With the iPad switched 'On,' it plugs directly into the 30 pin port and automatically prompts you do download the App on the first use, otherwise it launches the App.

The box it comes in is nothing fancy, but functional and the instructions while brief, are straight forward and explain what the App does and details the probes operating parameters, which for this probe is apparently: -30°C to +150°C with an estimated accuracy of +/- 0.2°C at 25°C.


Sous Vide system monitoring, kettle profiling, ambient room temperature monitoring and profiling, overnight Fermentation condition monitoring... the Homebrewing applications are many and at €55.99 plus shipping my expectations were quite high.

The manual is sadly hilarious.

"The product is not to be used for medical or for public information, but for home use only." What on earth does public information mean?

When I bought this online it was described thusly, "Pferde Hunde Katzen Tier Thermometer für Ihr Iphone iCelsius Pro," which is veterinary use. Very curious. Ahh, medical use but not for Humans...

"Do not use the iCelsius... in or near water. Only the metallic tip can be immersed." Thanks for the clarification. The original pics certainly show that the probe is not waterproofed...

 ...yet what I received has had clear attempts to cover the stainless steel shaft-wire interface with waterproofing and shrink wrapping. So is it waterproof? I don't know. The packaged product is not as advertised.

"Avoid placing your iCelsius sensor near a source of heat or exposing it to sunlight (even through a window)." Are you kidding? In what circumstances do you mean?

A Temperature Sensor is for measuring temperature, or so one would normally expect, for answering the questions, How hot? How cold? is it not?

So, the best part of €60,00 down and the manual is cautioning me against using this for measuring heat.

Is this some kind of Scam!?!

Aginova and TFA Dostmann you have some answering to do!

So, onwards and upwards, lets see what this thing can do. I put a hole in a rubber bung, and inserted the metal part, the stainless steel probe, through the hole and then pushed this into the brass thermowell on my brewpot. I pushed the probe all the way in until it made contact with the end of the thermowell and then backed it out just a touch so as not to be in direct contact.

Now, yes I know that there will be a delay in temperature measurement due to the air pocket in the thermowell, for this reason I allowed the system to stand so that the temperature in the air pocket stabilized, but I didn't expect the probe to read more than 5°C low at boiling point and similarly throughout the Mashing Temperature Range. Even the original dial thermometer that came with the Thermowell was more accurate than that, not accurate enough but still, more accurate that this iCelsius Pro Temperature Sensor.

Damnit! So, I have to test the bloody probe. I tell you, this is not what I thought I'd need to do.

Into the manual, check the Troubleshooting tips, yeah, yeah, done all that; onto the websites, can't find didley squat. Search the net? Nada, just glowing praise and advertorial material all about what it can apparently do.

My results from a simple calibration check for this probe.

Using two, separate, Laboratory quality temperature probes, one of glass and one digital, along with the iCelsius Pro sensor, all used at the same time, I measured several  stable temperatures as below:
1: < 0°C (pobes encased in frozen gel pack), at
2: 25°C (probes exposed side by side to ambient air temperature at the Listed Calibration Temperature)  at
3: 30°C (probes exposed side by side to ambient air temperature in a warm room, indirect sunlight) and at
4: 100°C (probe/bulb/sensor ends immersed in boiling water: altitude approx. 10.587 meters above sea level).

These are the results:

< 0°C




iCelsius Pro + iPad App 

(-30°C - +150°C)(+/- 0.2° @ 25°C)??? 
(-50°C - +300°C)
(+/- 1° -50°C - 150°C)
(-10°C - 110°C)
(mercury column)

Now, if I were just testing against one thermometer, I'd have to rightly ask which one is inaccurate? But when I have both a digital and analog thermometer, which I've relied on for reliable temperature measurement for years, both in complete agreement, for my money that tells me the new kid on the block has some serious problems.

Now, the application itself. It's nice, its clean, It has Bling! BUT, its next to completely useless. It requires that no other application is running at the same time. If the iPad goes into Sleep mode, then all data is lost. It cannot operate in the background monitoring a data stream from the sensor. Unless you export the data at the end of your session the data is lost. It has no archiving capability, No History capability, you cannot vary the time scales or the sampling rate, and it MAY interfere with wifi access.

It is, in essence, a Kiddy App for entertaining primary school students whilst trying to teach them a little something about science and the art of measurement. The probe app combination, unfortunately, is unreliable, inaccurate, incapable of documenting AND safely storing, measured data over time.

What this means is:
a) if you wish to Monitor your Sous Vide Cooking Pot, for HACCP purposes, it's wildly inaccurate especially if you are trying to monitor/control temperature fluctuations at the 0.1°C - 0.5°C accuracy level. There is no data protection or historic record (date, time, temperature measurements) of your session, and the only way to get data out is to manually send the data during or at the end of the session.

b) if you wish to profile the thermal capacity and rate of heat exchange in your brew kettle, identify ramp times and monitor your Mash Temperatures within a 3 - 5 degree range of accuracy, then this probe is also wildly inaccurate. Historic Data recording of temperatures from brew sessions is not possible for reasons stated above, unless you manually export the LIVE data.

c) if you wanted to use this to monitor fermentation temperatures over a period of several days? Forget it! The max operating time is one battery charge for your iPad as it uses the same 30 pin port as your charge cable. Second, if your iPad goes flat, looses charge, etc. then all data is lost. This is a particular bugbear especially if you wish to determine the stability and seasonal profile of ambient temperatures in you Fermentation Chamber, Cellar, or Room.

All in all, the iCelsius Pro Temperature Sensor and App are a complete waste of time and money, as well as being inaccurate and functionally useless.

How would I rate it?

To quote the acerbic TV Personality, Chef and Actor, Bernard King, "Minus Five!"

Until next time,
It's Your Shout, Mate!

The above review is based on ONE probe from iCelsius, obtained via Amazon, from a 3D party provider.

'Biggles and The Red Baron' Ale.

This started out as a Mongrel Dog Brown Ale experiment. A dog of a beer: A mongrel in that it was made of bitsa this and bitsa that; Brown as I didn't have enough pale malt; And, an Ale because I'd exhausted all my Lager Yeast.

It turns out that someone else somewhere has brewed a Brown Ale and called it dog: Brown Dog Ale. But, I reserve the rights to, "Mongrel Dog Brown Ale" though, if that's alright by you  ;-)

In the end this dog of a beer has turned into a beautiful pale gold/copper red ale. It used German malts and, English hops & yeast. German, English, Red? Yeah, Biggles and The Red Baron just sandwiched me in a slam dance!

So lets start.

Grain Bill was 35% Pilsen Malt, 20% CaraAmber, 20% home roasted Amber Malt made from pilsen malt & guestimated as similar being to a Crystal 40, and 5% Weizenmalz. Grain conditioned with 3% water by weight for 30 min prior to milling, and milled using an industrial quality corona type mill with steel plates. The conditioning results in  larger pieces of husk while the kernel is shattered into smaller pieces and lower flour production - I like it, Nice! Must tra another crush using my stone mill and see the difference, I suspect more flour and shredded husks. But does that really matter with BIAB?  Ok, BIAB process, single infusion mash at 65°-70°C for approx 1 1/2 hours in 24l of Hamburg tap water. Pre-boil Gravity was 1.032 and Post-Boil was 1.039 (predicted was 1.025 and 1.031 respectively.)

Boil was for 90 min and the Hop Schedule was 15g East Kent Golding (EKG) at 75min, 7.5g EKG at 30 min and 7.5g EKG at 5 min for a total of 15 IBU estimated however on tasting it seems much more bitter than that. A hop sock was used to contain the pellets and the hot break settled out well resulting in very clean, clear wort on transfer. Cooling was Slow Chill (check out the No Chill Method for more info) using a stainless steel fermenter with weighted lid and air lock, left out overnight. Ambient Temp was 5-10°C o/n not including wind chill factor. Current daytime ambient temp in the shade is 12°C.

Due to the cooling method chosen IBU estimates need to be adjusted by an extra 20min (apparently) due to the extended contact of disolved hop element with the hot wort. Yeast to be used is Nottingham and Safbrew S-33 because the yeast is old and I want to use it up. (perhaps a flavour mistake in the making, we'll see.) Yeast Starter made using Vitamalz 'alcohol free' Malt Beer. The plan is to Ferment in Primary for 5-7 days, then Dry hop with 15g of Fuggles in Secondary  for 7 days before transferring to the keg for conditioning, priming/krausening it with 500ml of unfermented wort retained from the boil. All in all this beer looks like its a flyer imbued with lots od daring do and dashing good looks. Let's wait and see how it performs when called to duty and put into service.

The brew day was conducted outside, so we could monitor the bbq and the kids. Mash temp was a bit dance-y due to the wind factor: I might have to insulate the kettle next time. The pump worked like a charm and all in all this BIAB caper is shaping up pretty well.

My Brewing Rig. 34l Fowlers Vacola 'Royal' Preserver (Model K) fitted with false bottom to protect the bag from the exposed parts of the element. Brass self sealing hose fittings, silicon hose, Electrolux Dishwasher Waste Water Pump (new), iCelcius Temperature Probe connected ot an iPad 1.

Now, I saw a vary poor video of some bloke using a dishwasher pum to circulate his wort a long while back and nothing since or by anybody else. It's what gave me the idea to do this and What A Little Bottler! Very quiet, very effective and for these small Urn based systems a very easy upgrade and enhancement to implement. You get more even heat distribution, nice clear wort and... basically its a poor man's Braumeister. Of course, there are a few things that still need to be done, on the protect it from water spills and leaks etc side of things but as a proof of concept, Bonza!

Here's the wort, end of boil, hed up to the light it's not as Red as it looked but I'm very happy with it. This is in the same area of colour as one of my favorite Czech beers: Krušovice Královský Pivovar.

Until next time,

It's Your Shout, Mate!

Sunday, February 17, 2013

Parisian Essence

Was doing a bit of research on an "antique" brewing ingredient, "Parisian Essence." Now, Parisian Essence is a Caramel type III food coloring and is frequently used in beer manufacture to control Beer Colour. What I wanted to know is how to spec it for use in a Brewing Program. Simple question, a coupe of hours of internet research later and a few beers and I have an answer:

Parisian Essence is a Caramel Class III (E1150c) product. The composition of Caramel III is more ore less as follows,

Composition: Plain ammonia caramel, Class III
Appearance: Dark brown viscous liquid
Odour: Characteristic odour
Colour (EBC): [approx.] 33,000
pH: 5
Extract (litre°/kg): 245.1
Total Apparent Solids (%): 65.5

So, to add this to a brewing program like Beersmith, I entered it as  "Grain" thus:
Name: Parisian Browning Essence, Origin: Australia, Type: Adjunct, Color: 33000 EBC, Potential: 1.046 SG, Max %: 0.1%, Inventory: 0.1 kg, Price: 17.00 €/kg. The tricky part was working out the Potential but somehow through various websites that I can't recall now, ended up with the above.

If you don't have access to Parisian Essence or some similar Browning additive, you can DIY it on your own. This seems to be the standard, 'go to' recipe getting around the net. I made this once before but didn't take the blackening far enough at.

Parisian Essence (source)
Preparation time: 15 to 30 minutes

1 cup sugar
1 cup hot water

1. Melt 1 cup of sugar in a medium heavy saucepan, over a low heat.
2. Stir constantly until sugar is burnt black and smoky. Use of an exhaust fan is highly
3. Remove from the heat and allow to cool a little.
4. Add 1 cup of hot water a drop at a time.
5. Be sure to add the hot water very slowly, to prevent spurting.
6. Continue adding the water until the syrup is smooth.
7. After all the water is added, stir again over low heat until the burnt sugar becomes a
thin dark liquid.
8. When cool, pour into a bottle.

Recipe Notes
Parisian essence will keep for years and the intense heat under which it is cooked destroys all
sweetness. A few drops will go a long way. Use this to darken gravy, fruit cakes and for staining
fabrics for various craft projects.

Until next time,
It's Your Shout, Mate!

Thursday, February 14, 2013

Real Ale, Medieval Style

The are a number of issues that relate to Medieval Brewing that bug me and seem to be missed or feintly addresses by recreationists. Whilst some seemingly scholarly work has been done replete with references here and there the problem at heart is one of not understanding the social dynamic in which the activities of brewing were taking place.

It is widely acknowledged that much of the brewing was carried out by womenfolk. That much is clear. What is not so clear is how alewives brewed, managed temperatures and times in the brewhouse, or if this was ever of any concern to them, in the first place? The reason for this, I feel is that most of the modern hobby brewers doing research into period brewing, like me are men, yet unlike me, they have no background in the household or kitchen arts. I believe such a background is essential for trying to unravel some of the brewing mysteries of the past.

The Brewers House
Lets take a look at some plates purportedly representing domestic brewing, perhaps, in the Middle Ages (medieval times)...

This first image depicts what is supposed to be a Master Brewer, who appears to be a man (monk?). Here there are a few point worth noting. First is the well outside; next is the smallish fire with chimney, which appears to heat part of the base of the tun; third the large tun appears to be mostly made of wood, and has a built in mash seive; then, there are what appears to be hops on the floor at the brewer's feet and distilling apparatus on the shelves behind. 

Such a sweet little arrangement don't you think? I want one!

So, here's a question, where are the buckets and the fermenters? Where is the fuel? Is the fuel wood or coal? Is this an accurate depiction of medieval brewing at all?

Is this next picture, the gender is right, AND I believe the arrangements are also accurate. Here we see a fire place. Next to it is a large tun and at its base what appears to be a metal pot. We know that these could have been made of bronze, copper, iron or pottery. This leads uy to the question, Is the tun directly heated by the fire, If so, how? Was the water heated in the pot and then added in periodic additions to the tun? Is this tun used for mashing at all? Or, is it just for grain storage? I suspect it is for grain storage, as indicated by the rake sitting on top of what ever is in the tun.

We also see the alewife tipping fluid into another tun. This appears to be a mash tun and the alewife appears to be making a hot water addition. Think about this for a minute. The boil kettle and the pail used to transfer the water to the tun are about the same size, but nowhere near the same size as the mash tun. To me this indicates a step mash process that is dictated by the size of the equipment on hand AND the ability of the alewife to lift and move volumes of water. It is my conjecture that the kettle and pail would have been not much more than 20L, roughly 5 gallons, in volume.

Next, we see in the foreground, a smaller tun with boards supporting a basket. this basket would have been used to separate the spent grain from the wort, and after cooling the wort would have been pitched with Barm and transfered to the open kegs for fermentation. What we don't see here is Hops, which indicates to me that this space was dedicated to the brewing of fresh ale.

Ale and Beer
Prior to the 1500's, in England, beer and ale were two decidedly different drinks. Both were made with malted grain however ale was generally made without the addition of supplementary flavourings, whilst beer tended to include various gruit (grout) concoctions in its manufacture. It seems also that another defining feature was that beer also tended to involve a post-mash boil, necessitating additional  equipment.

Another interesting fact seems to be that in the later part of the middle ages attempts were brought to bear to regulate Ale manufacture in-so-far as defining what could and couldn't be included in ale. This seems to mirror similar development in Europe, in relation to beer. It is worth noting that this led to a situation where ale brewers who sold product to the public were not allowed to brew beer and vice versa. It is unclear if this delineation also found its way into private manor houses although historic record seems to indicate that at least in the King's household, such division did exist.

Medieval Time and Kitchen Timings
One of the intriguing points often neglected by people curious about period brewing is the concept of time and how it was measured, if it ever was. We know that the concept of Time, its passing and the need to be mindful of it in the kitchen, existed well before the middle ages, but how did medieval cooks or brewers "know" how long to leave the mash so that a sweet wort could be extracted from the malted grains?

We know that such devices as Clepsydrae (water clocks), Sundials, candle clocks, and even sand-filled Hour Glasses did exist however, by and far, such devices were usually far too expensive for the typical brewer's house. We know that in many places there were churches or monasteries near enough that when they sounded the bells for Prime, Tierce, Sext, None, etc. the community would hear it. We also know that monks would often chant set prayers or psalms to mark of short periods of approximately the same time. It was well know at the time that the day was divided into 12 portions, so in combination of the church bells and a stick in the ground it would have been relatively easy to estimate the gross passage of time.

However, there were also other ways for kitchen cooks or brewers to calculate time. For example occasionally reference to a furlongsway (the time it takes to walk an eighth of a mile, 2.5 min) or a milesway (time to walk a mile, 20 min based on 3 miles to the hour) but such measurements are almost pointless near a fire unless you had a very practiced knowledge of the passing of such a portion of time or some hapless waif that was at your beck and call.

It is my conjecture that cooks knew how long it too to boil and egg, how long it took to bake a loaf of bread, how long it took to boil a set amount of water and that these would have been the reference measures that any good alewife or brewer of the times would have known like the back of their hand. Household brewing would not have occurred in isolation of the activities of the rest of the house, especially the kitchen.

Determining temperature without a thermometer
Another facet of interest that gets panhandled away is the concept of medieval step mashing and uncertainty in accurately assessing and hitting designated temperature steps AND why medieval brewers may have even bothered with this. 

From the picture above, it is clear that not all medieval brewers may have had access to a heated cauldron and crane in which they could gradually raise the mash temperature and control the exposure of the mash to heat. This concept in of itself is ludicrous, so much so that it would seem to be a very rational basis for discounting step mashing altogether. The question here is why would medieval brewers need access to such large equipment and precision control? 

The simple answer is that they didn't such equipment was far too expensive, not to mention unwieldy.  How many hobby brewers today, would think to use a crane to move a pot of hot liquid off of a fire and then back onto it, without spilling the liquid inside of it? Crazy? 

No, the smart answer is to move the fire. (Check this video to see how some northern brewers have solved this issue for their brewed over an open fire system.)

Given the equipment constraints of medieval brewers it is logical and sensible to consider an alternative brewing senario, that of a stepwise mashing schedule borne out of necessity and practicality. It is not too difficult to conjecture that brewers of old understood that by brewing in a certain way produced better ale and the better the process and the more diligently it was followed, the better the final product.

First, most detractors of this idea point out, rightly so, that in medieval times they did not have thermometers. But one doesn't need a thermometer to know heat and to estimate it with a reasonable degree of accuracy, at least for what was required in a kitchen or in an early brewery. What follows is a table of associations that anyone with a semblance of intelligence could determine for themselves.

Temp °C
Ice appears in the water or it is solid
Very Cold
noticeably cold to the touch
slightly cool to the touch
neutral, blood warm, warmth of mother's milk
slightly warm to the touch
uncomfortably warm, will turn skin red
too hot to touch without risk of injury
water surface begins to shimmer and move
Slow Boil
noticeable small bubbles forming and rising in the water
Rolling Boil
noticeably large and explosive bubbles rapidly rising to the surface

Now, can we comfortably say that brewers in medieval times had common knowledge of the benefits of resting at specific temperatures? Notably 40-45°C, 50-55°C, 62-65°c, 68-72°C and, 76°C.

No. No we can't, but we can't discount it either, just because it might have been based on undocumented, experiential trial and error knowledge. Let's face it, they did not know about Yeast per se but know that to get a ferment going they needed to pitch good, fresh barm into the cool wort, and if it was too hot, it didn't ferment. So here's where I open my mouth to change feet, so to speak...

Of the brewing and mashing of malted grain to make ale
What follows is my considered opinion on how an alewife would have typically made an ale using the tools available. Consider the following brewhouse...

From the picture above we have small water additions being made to a mash tun. While it is not entirely true that when you add two equal volumes of water to each other, volumes at different temperature, that the resultant temperature will be midway between both, because of temperature losses to the system and the surrounds, for our purposes here, we'll consider it thus.

Extenuating factors: in the brewhouse above there is a fire burning, gradually increasing the ambient temperature, and the temperature of all containers in the room. Most of the containers in the room are made of wood. Let us consider that the heat losses to the tun and other wooden utensils is less than 2-3°C especially with a good fire heating everything up along the way. 

Let us also define  the size of a bucket or pail as 3 imperial gallons, 13.6 (or so) liters, and that the ambient temperature of the grain is around 13°C - it's cold at night when there's no fire in the brewhouse.  Let us also consider the possibility that there's an old bucket hanging around that leaks a little and it runs empty in about the same time that it takes to bake a loaf of bread, or thers a stick outside with a nominally calibrated shadow path that somehow corresponds with the local church bells; (I like the leaky bucket idea myself.) 

So, let's begin:
  1. Draw one pail of clear water and set it to warm on the fire
  2. Into the tun place one pail of malted grain
  3. When the water is slightly cool and not quite blood warm, splash it over the grain in the tun to make thick gruel    --- (guesstimated temp should be somewhere around 24°C, Acidulation Rest)
  4. Draw a fresh pail of clear water and set it to boil
  5. When the water begins to leap and tumble, add one pail of roasted malt grain (amber) and the boiling water to the tun, stir well
  6. Allow the mash to steep, for the time it takes to bake a loaf of daily* bread, or for a double milesway    --- (guesstimated temp should be somewhere around 55°C, Protein Rest)
  7. After this, draw one pail of clear water and again set it to boil
  8. When the water begins to leap and tumble, add it to the gruel and stir well
  9. Allow the mash to steep, for the time it takes to bake a loaf of daily* bread, or for a double milesway    --- (guesstimated temp should be somewhere around 68°C, Amylase/Sacharification Rest)
  10. After this, draw one pail of clear water and again set it to boil
  11. When the water begins to leap and tumble, add it to the gruel and stir well
  12. Allow the mash to steep, for the time it takes to bake a loaf of daily* bread, or for a double milesway. The mash should now be too hot to touch    --- (guesstimated temp should be somewhere around 75°C, Mash Out/Denaturing Enzyme Activity)
  13. Arrange a wicker or reed basket over a small barrel, line with fresh clean straw and ladle the hot mash into the basket until the barrel is full
  14. Repeat until all the grain has been removed from the mash
  15. Cover with a linen cloth and set the barrels of young ale aside to cool
  16. When cool, add fresh barm to each barrel, mix well and transfer the young ale to barrels to age
  17. Check the barrels each day and collect the barm that rises to the surface
  18. When the barm stops rising the ale is ready to taste. If it is good it is ready to serve.
* just playing a little with words and images here, ignore the floury (sic.) bits if you wish.

A few final comments should be inserted here as well. The forst two steps, why would any alewife of medieval times bother with them, and not go directly to a higher temp? 

First, malted grains weren't as modified in medieval times as they are now, thus requiring more effort to manage the proteins. Next, some conjecture lies in the idea that without a boil, the proteins needed to be more readily available in liquid form to maximise the healthfulness of the drink. 

Thirdly, many cooks of old dealing with grains and and dried pulses knew the value of allowing them to steep in warm water prior to cooking as this directly improved the cooking process, thus it is not such a significant leap of faith to consider that low temperature steeping of the grain would have been considered a necessary first step, however above we have two grain additions, one steeped and one not It seems to be an accepted fact that roasted grain was used as well as unroasted grains in the mash. 

Its also quite possible that the water may have been heated to just warm, approx. 40°C placed into the tun and a second batch drawn and heated prior adding the whole grain bill then leaving it to steep. This is the great thing about experimentation with relatively unknown ye olde worlde processes. 

So there you have it, this is my personal interpretation and rationalisations around what might constitute a (early) medieval ale brewing process. 

Until next time,

It's Your Shout, Mate!

References (in no particular order)

Medieval Brewing accessed on 2013.02.10 accessed on 2012.02.13

Medieval Timekeeping