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.
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!