Thursday, 16 October 2014

German brewing in 1960 - fermentation and lagering

Isn't this fun, our stroll through the kitchen garden of the past? Just keep an eye out for wasps.

We're going to kick off with fermentation, the heart of the brewing process.

"Fermentation.— Standard practice in 9 of the 10 breweries visited was to arrest fermentation at a suitable attenuation for racking to the lager cellar. Temperatures were in the range 40-48° F. and much variation in yeast behaviour was apparent, comparable attenuations taking from 5 to 14 days. All the larger breweries had pure-culture yeast propagators in operation and yeast washing was general. Liquor at 34° F. was used and storage was generally under this liquor as a thick paste. Pitching rate was measured volumetrically: from 0.3 to 0.5 litres of the pasty yeast was pitched per hectolitre of wort, i.e. approximately 1.5 lb. per brl. for 1045° wort. Fermenting vessels were predominantly of ebon or aluminium, with newer installations in stainless steel but rarely enclosed. Mixing of worts often took place in large starting tanks and attemperation was by cooled drinking water at 34° F. It was common practice to skim off the resinous scum with a perforated scoop just before racking."
Journal of the Institute of Brewing, Volume 66, 1960, page 500.

The obvious question is what did the tenth brewery do? And how did the nine stop fermentation? By cold crashing?

Let's so how that compares with British practice. This is the fermentation record of Barclay Perkins Export from 6th November 1962:

You can see that it was pitched at 45º F and most of the fermentation was round 48º F, putting at the top end of the German range. While at 10 days, the primary fermentation was on the long side. I was going to compare the pitching rate, but unfortunately I can't understand the yeast details in Barclay Perkins Lager logs. Can you tell me what 61/3 + 13/3 means? I thought not.

Instead I've looked at Whitbread PA from 26th October 1959. A beer of 1039.5 which received 0.8 lbs of yeast per barrel. About half the German Lager rate. It makes sense that you'd need to pitch a lot more yeast in a Lager.

Barclay Perkins both repitched yeast from earlier brews and used pure propagated yeast in their Lagers. They never used pure yeast in their top-fermenting beers, only repitched harvested yeast.

This doesn't quite tally with what I've seen in the fermentation rooms of small Bavarian breweries. True enough, the fermenters are open. But the wort isn't cooled with attemperators inside the fermenter. The whole fermentation room is kept refrigerated. Fermenting vessels mostly seem to be made out of stainless steel, though it's hard to tell when they're filled with wort.

Now lagering:

"Lagering.— In German cellars it was essential to allow tank pressures to rise to between 6 and 9 lb. per sq. in., as no further artificial carbonation was allowed. Bentonite was commonly added to the lager tank, and bunging tended to be individual, with not more than 3 tanks in a column. Cellars were often maintained at a temperature just below freezing, particularly with export beers, to allow maximum precipitation. Storage periods varied from 2-6 months, with one extreme case of 9 months in a brewery with extensive storage space. New tanks were of aluminium, but pitch- and glass-lined iron tanks were common and many old wooden casks of up to 50-brl. capacity persisted in Bavaria."
Journal of the Institute of Brewing, Volume 66, 1960, page 500.

The original method of carbonating Lager was to seal - "bung" - lagering vessels after a certain time to allow pressure to build up inside them and the beer to naturally carbonate. This was the process recommended for brewing Harp Lager in the early 1960's. I'm sure they quickly dropped the practice and switched to artificial carbonation. German brewers had no option, being limited in their actions by the Reinheitsgebot.

The classic lagering period is 1 week per degree Plato of the beer. So a 12º Pilsner needs 3 months lagering, an 18º Dubbelbock 4.5 months. 6 months seems long for anything other than a Bock. From my inquiries at various Franconian breweries, modern lagering times are between 2 and 4 months. At least amongst small, old-fashioned breweries. I'm sure they're much shorter at the big boys. If they bother lagering at all.

Not sure how many still use wooden lagering vessels, even in Bavaria. The only ones I've ever seen in use were at Brauerei Schmitt in Singen, a museum brewery. Even there it looked like they were being replaced by metal tanks. And the only more old-fashioned breweries I've ever seen were communal Zoigl brewhouses.

Next time it will be packaging. How exciting.


Pivní Filosof said...

About the open fermenters, What I've seen here. Older breweries, or breweries that still keep their old fermenters: they are enameled steel. New breweries, or breweries that've been modernised: stainless steel. In some cases, even if the room is refrigerated, the fermenters have cooling tubes that are used to keep the temperatures steady during fermentation, sometimes they are visible, others, will be in the outer case of the fermenter.

Alistair Reece said...

I find the lagering time interesting given the canonical version of the creation of Pilsner Urquell being that the mash for the first production batch was on October 5th 1842, and it was first served on November 11th. A total of 31 days from start to finish.

Anonymous said...

Alistair Reece:
Could it be that the first batch was schenkbier/winterbier (ca 10-11% balling) and not lagerbier/sommerbier (ca 12-14% balling)? That would give enough time for fermenting and storing the beer for a lenght of time which wouldn't be unusual for a schenkbier/winterbier produced in Bavaria at the time (schenkbier was typically stored 4-6 weeks before being served). Today of course the term lager beer is used for any beer that is bottom fermented, and PU and SABMiller probably use the term as it is currently understood.

Pivní Filosof said...

Modern PU is an 11% beer. (11.something, actually), fits in the category Ležák (11-13º Balling), and many people have it for a 12. Anyway, 4 week lagering is not rare in these lands (CZ) for beers of that strength. When I asked a brewmaster friend of mine why didn't they lager longer his answer was "because it doesn't get any better".

Gary Gillman said...

That's very interesting Ron. I'm starting to convince myself that the longer the storage, the more likely the modern stenchy sulphur notes of much lager would have been aged out of the beer. I.e., elimination of "green" flavours which home brewers talk about.

In the immediate pre-Jackson period, one U.S. beer was still long-aged and not only that, it went, um, the full nine yards:'s9montholdperfectionbeer

Of the reputed U.S. beers available in the 1970's, e.g., Ballantine IPA (now returned but haven't tried it yet), Yuengling and Stegmaier Porters, Anchor Steam Beer, Rainier Ale aka The Green Death (7% ABV, throwback to 1800's English mild ale), the Horlacher is the only one I could never track down.

Note how the pamphlet description uses almost the same term as the 1960 Brewer's Journal, "adequate storage space". I find that odd because by definition anyone proposing to keep beer 9 months has to have the space to do it. It kind of begs the point to say I don't have the space to age beer 9 months because I need to ensure my other production requirements are met. Putting it a different way, maybe having adequate storage space meant being under-capacity - brewers, like any business, can make a negative into a positive...


Rob said...

Whats with the 3 different measures starting on day 3?

Did they split into 3 different fermenters?