Saturday, 13 September 2008

Ale Brewing circa 1850 (part two)

Today it's details of the fermentation process.

A maximum pitching temperature of 66º F in cold weather and 62º F in warm weather was suggested by Loftus. (Source: "The Brewer" by William Loftus, 1856, page 44.) Though for hard-water worts slightly higher temperatures were needed than for soft-water ones. (Source: "The Brewer" by William Loftus, 1856, page 45.) Similarly, hard-water worts required a greater quantity of yeast to be pitched: 5 to 6 pounds per quarter of malt as opposed to 3 to 4 pounds for those from soft water. (Source: "The Brewer" by William Loftus, 1856, page 45.) [From one quarter of malt between 2 and 4 36 gallon barrels of wort was produced.]

Fermentation could be speeded up beating the yeasty head into the fermenting wort. This process also meant that less yeast needed to be pitched, something Loftus found a good idea. "By thus blending the yeasty principles of produced by the beer, we can make a smaller quantity of foreign yeast suffice; and it is a desirable object never at ant time to use more of the latter than is absolutely necessary to effect conversion. (Source: "The Brewer" by William Loftus, 1856, pages 45-46.)

The fermenters were kept closed, only being opened to add yeast or sample the gravity. When the weather was cold, the fermentation room itself kept closed to maintain a constant temperature. (Source: "The Brewer" by William Loftus, 1856, page 46.)

The degree or attenuation was determined by a variety of factors: original gravity, air temperature and how long the beer was to be stored. In general, strong worts could be attenuated more as they would still retain enough unfermented material to give the beer body and to leave some extract for secondary fermentation. (Source: "The Brewer" by William Loftus, 1856, page 46.)

Beer was not attenuated as much in cold weather as in warm, again to help secondary conditioning. If it was intended for immediate consumption, beer was moderately attenuated, so there were enough sugars left for conditioning, without leaving it too thick and heavy. (Source: "The Brewer" by William Loftus, 1856, page 46.)

Strong Keeping Ales were attenuated as much as possible. The greater the degree of attenuation, the more easily they blended with other beers. (Source: "The Brewer" by William Loftus, 1856, page 46.) But, in order to leave plenty of fermentable material for a long secondary fermentation, they were cleansed at a higher gravity than beers intended for immediate use. (Source: "The Brewer" by William Loftus, 1856, page 49.)

Hard water worts did not attenuate as easily as soft water worts and often needed extra yeast. (Source: "The Brewer" by William Loftus, 1856, page 47.)


Anonymous said...

Blog readers,

My dad is now at the Copenhagen Beer festival. Questions will be answered next Monday.

Mr anonymous I have the job of deleting your attacking comments.

Son of Ron

Zythophile said...

Keep it up, Son of Ron (Ronson?), you're doing a fine job defending yer dad against the goblins

Anonymous said...

Son of Ron, forget about yer Dad's beer stuff. Get going on your own blog.

All those Dutch posts about WW2 tanks and armoured vehicles need translating. Hop to it ;)

Anonymous said...

OK, I'm sure there's an obvious answer, but I'm not too proud to admit my ignorance. Why do beers with hard water not attenutate as easily? I had never heard that, but find it interesting. Love to here what the reason is.

Son of Ron, great job. Thanks for your efforts in policing the morons.