Vacuum fermentation

There have always been fads in brewing practices. And one processs that was attracting a lot of attention in the late 19th century was vacuum fermentation. Also called the Pfaudler system.

I'll leave it to the article to explain exactly what a vacuum fermentation is.

"The system of conducting fermentations in a vacuum, or partial vacuum, is not very well-known in this country. Indeed, we do not call to mind any instance where this system has been tried by English brewers. It is, however, gaining ground abroad, and its advocates speak very highly of the results obtained. The principal brewhouse in Europe using the vacuum fermentation i situate at Helsingfors, in Sweden, and we are enabled to give a few details of the process, as explained by Professor L. Aubry, the well-known Munich expert. Simplicity is claimed for the whole system. The wort undergoes its primary fermentation in enamelled steel tanks, under a partial vacuum. The pressure is reduced to, and kept at, 450mm., carbondioxide being drawn off as formed, and a suitable charge of air let in to maintain this degree of pressure. When the primary fermentation is finished, and the secondary started, the beer is run into storage vats, and is livened up, or “krausened” as it is called. with 10 per cent. of fermenting wort, and eventually subjected to fining. At the end of a period of four weeks, the beer is ready for tapping, and some judges have pronounced it superior to beers produced on the old lines. When necessary, the carbondioxide collected from the fermenting tanks is returned, after liquefaction, to the finished product."
"The Brewers' Journal, 1898", page 400.

A year after this article was published, a UK brewer did invest in this system. Allsopp bought a Pfaudler system to produce Lager in Burton on Trent. It wasn't a great success and a little more than a decade later the plant was in disuse. It was eventually shipped to the Alloa Brewery in Scotland, where it was used to brew Lager.

What were the advantages of this system?

"Such is the process. It now remains for us to examine into the alleged advantages attending its adoption. These comprise economy of space, economy of time, perfect cleanliness, and greatly enhanced ease of manipulation. A system which promises such obvious advantages demands careful inquiry, and this is what Professor Aubry has subjected it to. He says that there may be much truth in the existence of these points of superiority, but that the plant is very costly to erect, and equally expensive to maintain. Again, clarification, usually effected abroad by the use of beech wood shavings, has to be brought about by gelatin finings, and is somewhat difficult to perfect under the conditions followed out in the vacuum fermentation process. It is further said that the removal of the carbondioxide layer might expose the worts to infection, andpermit the introduction of organisms antagonistic to the yeast plant and the beer. Touching the yeast itself, it is quite conceivable that very careful selection would have to be practised in order to obtain a race capable of adequately fermenting wort under these altered conditions. Many yeasts would not thrive under such circumstances, yeasts that give healthy results under normal conditions of fermentation."
"The Brewers' Journal, 1898", page 400.

It took less space, was quicker and was cleaner. But, on the downside, the kit was pricey and it made fining difficult. (Nice to see confirmation that beech wood shavings weere used to clarify Lager.) Plus the yeast might not like it. It's important to remember that UK breweries weren't using pure yeast cultures and had multiple strains in their pitching yeast. If they reacted differently to the system, the character of the beer would change.

But there was one real killer disadvantage: beer brewed that way didn't atste as good as cask beer: 

"There is one objection that condemns any such system, to our mind. We refer to the impossibility of imitating the ripe and genial flavours of properly matured ales. No process has, as yet, been invented that supplies the flavours of well-matured cask beer. There is a soft roundness inherent in beers charged with nascent gas that never comes out in an article gassed under pressure. This is a point that has not escaped the notice of Professor Aubry, and he specially refers to the deficiency of the vacuum-fermentation beers in the smooth fine flavours associated with mature cask beers. We believe the apparent gain in time is but a loss when the result is a harsher article; for the public like to drink the best that can be supplied, and they are entitled to the best that skill can supply. The vacuum system will not take root and flourish on English soil, of that we are certain; but, as a development in brewing practice, it is interesting. The American brewer has long ago utilised the ideas upon which it is founded, but that only in lager-beer houses."
"The Brewers' Journal, 1898", page 400.

I'd go along with that: a naturally conditioned cask beer is always going to taste better than fizzed up keg beer.