Reusing Yeast: Wort Gravity

[TheOriginalDBS]

Question for minds greater than mine regarding what gravity your wort should be when reusing yeast....

So there’s generally two ways of reusing yeast. Method one is fermenting a low gravity beer, then racking it off the yeast cake (we’ll call this Gen 1) and dumping a higher OG wort on top of it (now Gen 2). Method two is taking the Gen 1 yeast and washing it, then making a new yeast starter with it, then pitching that into new wort.

my question is: with Method 2, what should the gravity of the yeast starter be? And in turn, what should the gravity of the second wort be?

For example: So if I start with 1.050 OG wort with Gen 1, does the starter need to be, say, 1.055? Or can it be normal starter gravity (1.036)? And does the second wort need to be 1.050? Or must it be 1.055+?

 

[balrog]

I do the overbuild method (3? 4? n?) wherein I buy a pack, 100b, and make 1.5L of 1.036-40, on a pc-fan stir plate, making ostensibly 300b. I save 1/3 (gen2) in the fridge and pitch the 200b in my ales. Then I repeat with the 100b saved. On and on.

Simple answer to your question I believe standard practice is to use 1.036-40 as starter wort when making a starter.

 

[downzero]

I think the answer to your question is normal starter gravity. But there's a simpler way to do this. Just take a portion of the yeast cake, put it in a sanitized mason jar, store that in the fridge, pour off the cold crashed beer from the top and pitch the slurry. There's really no reason to make a yeast starter unless it's to check the viability of the yeast slurry; your entire first beer was a huge starter. I normally keep a quart of yeast from a batch, and I can tell you from experience, that quart of yeast will probably make 2-3 more 5 gallon batches of beer, so if you pitch the whole quart, you will be virtually guaranteed to have beer on the other side of that fermentation.