Brewing tables from 1867-1871.

Found some interesting tables compiled by a brewery manager named C. Prandtl from Fürstenberg, as part of an article on how to keep detailed brewing records. The article was included in a Bavarian brewing journal from 1872. It contains alot of interesting information, but it requires some German language skills to make sense out of them which is why I thought it might be more fitting for this forum.


Here's a summary of the production of weissbier in Prandtl's brewery in the years 1870-71. Notice that they brew top fermented weissbier in the warmer months and bottom fermented weissbier in the winter months (like you would a lager beer). Also notice the different (and quite low) original gravities month by month, and also inbetween top and bottom fermented weissbier. In the article it is made clear that they use barley malt which is kilned, not air-dried, to brew their weissbier.


This table gives calculations for how much beer is produced by a certain amount of malt and hops, the efficiency basically, based on an average original gravity for each type of beer.


Here is a table with calculations for schenkbier (or winterbier) with an average original gravity of 12.49% balling.

Here are calculations for the lagerbier, or "sommerbier" produced in the year 1869-70, with an average original gravity of 13.9% balling. Out of 100 kg malt and 1.55 kg hops, 3.9 hl wort of 13.95% Balling, or 3.57 hl of finished beer is produced. 1.55 kg of hops per 357 liter finished lager/summer beer makes out to 516 grams of hops per US barrel. For the schenkbier the amount is 331 grams per US barrel. For the top and bottom fermented weissbier the amount is around 243-247 grams per US barrel.


Here's an attenuation table for lagerbier. Notice the span of original gravity of between 13.3-14% Balling (since a similar span of original gravities can be observed for the top and bottom fermented weissbier, I'd wager to guess that the same applies to their schenkbier).

 

It's easy to assume that weissbier equals weizen due to the dominance of Bavarian weissbier, and the prevalence of wheat in Bavarian weissbier brewing (today). I found some interesting statistics in a book from 1893 about the Bavarian brewing sector in the 19th century which puts this into perspective however.

According to the book (page 68), referencing another German author, in Bavaria in 1807/08 there were 480 weissbier breweries.
27 of which brewed only wheat beer.
419 of which brewed only barley beer.
34 brewed both barley and wheat beer.

For comparison purposes there were 4265 braunbier breweries.

 

Well Prandtl distinguishes between ober and untergähriges weissbier in the table. Additionally there's the "diary" for weissbier brewing:


As you see he distinguishes between obergährung and untergährung (see under bemerkungen), and the keller and wort temperatures differ accordingly (18 degrees R, or 22.5 degrees celsius for the top fermented wort, I'm assuming prior to yeast pitching since yeast is listed in the column next to the temps, 4.5 R, or 5.6 degrees C for the bottom fermented wort. The cellar temp is also lower for the bottom fermented weissbier).

 

I've been reading some about Bavarian beer legislation from the 1800s and from what I've been able to gather a law went into effect in 1811 which decreed that a maximum of 7 eimer of winter beer, and a maximum of 6 eimer of summer beer could be made from one scheffel of malt. From what I've read about old Bavarian measurments, the Bavarian eimer contained 60 Maass. One old maass was 1.069 liter, so 60 maass makes 64 liter in one eimer.

One Bavarian scheffel was 2.22 HL, i.e 222 liter. 1 HL of malt seems to differ in weight depending on various factors, but similar to the calculations of Prandtl above, they tend to hover around 50 kg per HL malt. 2.22 times 50 makes out to 111 kg for a scheffel of malt, give or take some kilos.

So as per the 1811 regulativ, around 111 kg of malt gives you 7 eimer of winter beer or 6 eimer of summer beer maximum.
7 eimer is equal to 448 liter.
6 eimer is equal to 384 liter.

Looking at the table from Prandtl for his Schenkbier, 1 HL of malt, or 49.6 kg, produces 2.07 HL of beer, or 207 liter.
2.2 times 207 is 455.4 liter.

Looking at the table from Prandtl for his Lagerbier, 1 HL of malt, or 51.92 kg, produces 1.86 HL of beer, or 186 liter.
2.2 times 186 is 409 liter.

He thus gets almost the same amount of schenkbier as is prescribed in the 1811 regulativ, 455 vs 448 liter, but he gets slightly more lagerbier, 409 vs 384 liter. That's without taking into account a margin of error.

Looking at the hops, according to the regulativ of 1811, 3 (Bavarian) pounds of hops were to be used for winterbier, 5 pounds for the sommerbier, per scheffel of malt. One Bavarian pfund was 560 grams. 3 times 560 is 1680 gram. 5 times 560 is 2800 grams.

Going by the regulativ of 1811, 448 liters of winterbier turned into US barrels is 3.82bbls. 384 liters of summerbier is 3.28bbls.

1680 grams of hops divided on 3.82 barrels is 439 grams of hops per barrel.
2800 grams of hops divided on 3.28 barrels is 853 grams of hops per barrel.

For Prandtl's beer my calculations above can be restated:

So both Prandtl's schenkbier and lagerbier is more lightly hopped than the 1811 regulativ prescribes, as per my calculations at least. His schenkbier seems to use a similar amount of malt per HL, whereas his lagerbier uses slightly less (resulting in more beer), than was prescribed in 1811 in Bavaria. It is interesting to note here the average wort strenghts that Prandtl provides, of 12.49 for his schenkbier and 13.95 for his lagerbier (although as is evident by the attenuation table, the original gravity of the latter shifted by almost a full percent in the year 1867, and the same was probably true for the schenkbier). An average of 12.49 seems like a reasonable original gravity for winter/schenkbier, and it doesn't seem unreasonable to think that the wort strenght might have been similar for those brewers following the 1811 regulativ (of course the regulativ allowed for less beer to be made from a scheffel of malt, so as to make a beer of a stronger wort).

There are more interesting aspects to these regulations (such as changes in 1814 allowing for 8 eimer winterbier and 7 eimer sommerbier to be brewed from a scheffel of malt), but I think I should stop here for now.

Sources for the regulativ:
Ueber die bayerische Bier-Polizei (January 1, 1859)
https://archive.org/details/jstor-40738429

Die Entwicklung des bayerischen Braugewerbes im neunzehnten Jahrhundert: Ein Beitrag zur ... (1893)
https://archive.org/details/dieentwicklungd00strugoog

 

I was hoping that such an estimation might be possible, although from having discussed a similar question with @JackHorzempa in the past, it seems like efficiency is increased in larger kettles compared to the home brewing scale, so I suppose one would need a calculation which took this into account. On the other hand, if the problem with the calculations for home brewing is that they undershoot the IBU "extraction" for larger kettles, which seems to be the issue, not that they overshoot, we could keep this in mind I suppose and still go ahead and try and figure out the theoretical IBUs.

Using http://www.probrewer.com/resources/tools/bitterness.php I attempted to calculate the numbers for Prandtl's schenk and lagerbier.
Numbers for the Schenkbier:
Original gravity: 1.050 (12.5% balling)
Final volume: 4.18 hl
Alpha acid: 4% (low balling it)
Mass added: 1.16kg
Time boiled: 120 minutes
IBUs: 28

Numbers for lagerbier:
Original gravity: 1.057 (14% balling)
Final volume: 3.57 hl
Alpha acid: 4%
Hop mass: 1.55 kg
Time boiled: 120 minutes
IBUs: 41

As per the hops used by Prandtl he uses several different varieties as per the Sudplan for lagerbier:
Württemberger
Holebau
Mischelbach
Pleinfeld
Spalt Ld (Landhopfen?)


Assuming that the winterbier decreed in the 1811 regulativ is similar enough to Prandtl's schenkbier, one could calculate the IBUs for it by using a larger hop addition and keeping the rest as is, but one intervening variable here is that from what I've read, Bavarian brewers used old hops for their winterbier (maybe a year old), and new hops from the latest harvest for their sommerbier. This might impact the IBUs quite a bit, since from what I understand the same practise is used by lambic brewers, and the result is that the hops lose (some? all?) their bittering qualities and are used for their preservative qualities instead. For the sommerbier it was also proscribed that Böhmerhopfen of excellent quality should be used, i.e Bohemian hops, whereas for winterbier landhopfen of average quality could be used.

Attempting to calculate the sommerbier as proscribed by the law of 1811 might be doable to an extent, with a large caveat attached. Here it goes:
Original gravity: 1.059 (14.5% balling, attempting to account for the lower volume vs Prandtl's lagerbier)
Final volume: 3.84 hl
Alpha acid: 4%
Hop mass: 2.8 kg
Time boiled: 120 minutes
IBU: 68

By changing the variables some slight changes can be made to the IBU number, raising the original gravity into 16% plato territory brings it down to 65, but it's difficult to bring it down significantly via higher wort strenghts, and lower wort strenghts would generate the opposite effect. Cutting the boil time isn't an option I think, if anything the 2 hours might be a bit low for Bavarian braunbier brewing.

68 IBUs isn't massive by contemporary craft beer standards, and with a relatively high wort strenght, and low degree of attenuation as was typical for 19th century Bavarian lager beer, resulting in a relatively high residual sugar content, it's not an outrageous number. But it is still higher than I expected. I've read in various written sources that some people preferred the winterbier to the summerbier due to the latter being too bitter (for example in an 1826 book on braunbier brewing), and there may have been something to that.

Feel free to point out irregularities or additional intervening variables which may effect the caluclations above, or render them useless . I'm very interested in hearing from any home brewers as to what they make of these numbers, as I haven't brewed a batch of beer in my life, which makes all of this theoretical for me. But I'm trying to spot the patterns and relationships that emerge from the numbers.

Edit: One such variable which I haven't accounted for is the issue of separate hop additions. If the 2.8 kg is divided into two additions, the first boiled the full 2 hours, the second boiled for one hour, the IBU number drops to 65 as per the 1811 lagerbier calculation above. So not a huge impact.

 

In order to be on the safe side, we could also assume a lower alpha acid content for the hops used, say 3.5% instead of 4%, in the 1811 lagerbier example the reduction in alphaacid content (together with the separate hop additions) drives down the theoretical IBUs to 57.

 

I noticed one mistake that I made. I should have used the amount of cold wort as the final volume rather than the finished beer. For Prandtl's Schenkbier the IBU changes from 28 to 27. For the lagerbier the IBU changes from 41 to 37.

For the hypothetical 1811 lagerbier the final volume should also be higher than the finished beer, which would reduce the IBUs by some units, going by Prandtl's lagerbier the volume lost between cold wort and finished beer would make up around 34 liter on top of the 6 eimer of finished sommerbier. Only altering the final volume and keeping the rest the same brings the IBU down to 62. Adding a split hop addition brings it down to 60. Reducing the alpha acid down to 3.5%, on top of a split hop addition, brings the IBU down to 52.

 

Do you know of a way to account for a larger kettle as a factor in calculating theoretical IBUs for a commercial scale (19th century) "recipe" like the one above?

 

Well braunbier was the term used in Bavaria for bottom fermented beers which used kiln dried malt. These were in turn divided into winter and sommerbier. At some point the sommerbier also becomes known as lagerbier (due to it being stored for longer), whereas winterbier also becomes known as schenkbier. The term braunbier lives on in Bavaria until at least the late 1800s when statistics and various other sources still distinguish between braun and weissbier breweries, whereas in other countries inspired by Bavarian brewing methods the term Bavarian beer, or Bavarian lager beer, or simply lager beer, becomes the term used.