Well the talk was really fascinating. It was geared more toward newer brewers covering general good fermentation and yeast handling practices, but there was a lot of good info.
The first topic was yeast starters. Wyeast smack packs are destined to inoculate a 5 gallon batch of beer per package at 1.040 or less. That doesn't mean that if you brew a beer of 1.040 that a starter isn't recommended, it's just not mandatory. Of course a starter will help with strong fermentation and better to ferment out diacytal and whatnot. After 1.040 the brewer should add an additional smack packet per 15 gravity points plus a starter. For instance: my house beer is a pale that has an OG of 1.060 and an FG of 1.009. To ensure good yeast health and proper attenuation I should use 2 smack packs with a 1000ml starter on a stir plate for 20 hours. I harvest and bank my yeast for 3 generations per wash, so the smack packs only pertain to the great grand parent batch.
The second topic was yeast starters. Your starter should have an OG of 1.040. The use of a stir plate really increases the viability of the yeast by 50%. With the use of the stir plate the yeast starter should be made 24 hours prior to pitching. After 20 hours the yeast will have mowed through all the available sugars in the starter, and it will go dormant. Too long on the stir plate can beat up the yeast quite a bit.
The next topic that was covered was temperature control. I think just about all of us already know the importance of this, and already practice it. Along with temp control was diacytal rest, cold break, hot break, and DMS.
The last topic that was covered was yeast harvesting, washing, and banking. This covered the harvest of yeast from your fermenter and some do's and don't's. For instance: it's not a good idea to toss fresh wort right on top of a previously used cake without washing it and being sure you have pulled only the viable yeast. From here you can put the yeast in slants and bank it to build up the cultures for future use. Each culture is good for up to 5 generations. After the 5th generation the cells have budded so many times that now you are left with only the most flocculant of the cells. For those of you who re-pitch may find that the third pitch is usually the best batch of beer from that culture. I asked about this, and the explanation I received was basically that by the third pitch the culture is still very healthy and now has grown accustomed to your brewing practices and environment.
All and all it was a very good discussion. My wife and I enjoyed the talk very much. I also asked the rep about the availability of wyeast products in the UK. He explained that 28% of wyeast's business is conducted in Europe with many distributors in Britain. He said if you guys contact your brew shops they can order any strain for you, but the shops should be stocking the yeast already.
