reusing yeast from a brew

Right now I'm brewing a brewferm triple, and will start a brewferm Abbey beer in a few days.

1) what are the advantages to reusing yeast from one batch to the next over a fresh sachet of yeast?

2) what is the best way to reuse yeast if you plan to use it strait away (or as soon as possible)

There is a good many shows on this Brewstrong you should give a listen. I am a firm believer that the first pitch makes a good beer, re harvest this yeast and use again makes a much better beer. The 3rd and 4th generation makes an incredible beer. Sanitation is key to this whole process or your yeast may not be good from batch to batch.

Be careful re-using yeast from big beers--I've read that you should't re-pitch from anything 1.070 or over.

Also be careful to re-pitch an appropriate amount of slurry--most people would tend to overpitch when re-using slurry. You don't need that much (consult the pitching rate calculator at www.mrmalty.com for help with how much to re-pitch).

Re-pitching slurry works great if you keep those things in mind. IMO it provides a great source of healthy, viable yeast. I'm not certain, but krausening might be the only better thing out there.

Thanks guys! I will reuse my year following the calculations! The triple I have is relatively could with only 1. 063 starter rather than the 1.083 advised by the style. Well, it was a simple kit so I'm happy enough with that.

You can re-use yeast from any batch. They just caution re-using yeast from high gravity beers as it has a higher chance of mutation. For some Belgians, Commercial brewers have to re-use from high gravity beers.

For re-use of slurry, I find Mr. Malty more of a guess and I don't agree with it's calculation of viability. When re-using yeast, I generally use about a quarter of the yeast cake for a beer of similar gravity. If the new beer is twice the gravity, I would use a half of the cake.

My reasoning for using a quarter of the cake: Generally, a finished beer will contain 6x the yeast that would have been the recommended pitching rate (this is true if you over or under pitched). I assume some will have died due to the weight of liquid on it in the fermenter. Thus probably a fifth would be correct, but I assume my collection and storage are not perfect, so I use a quarter. Never had a problem if stored in fridge and used within a month.