Yeast for a 2.5 gal batch

I have done about a dozen 5 gal extract kits and am in the process of transitioning to 2.5 gal BIAB batches. It's easy to re-calculate the ingredients from a 5 gal recipe until i get to the yeast.

So my dumb question of the day is… should i use a full packet of yeast for a 2.5 gal batch or should i use half and save the rest? Make a starter and save half?

I'm sure this has been discussed before, but i couldn't find a thread - a link to a discussion thread would be great.

Thanks!

Depends on what you are brewing, so I suggest using a yeast calculator like Mr. Malty to figure out exactly what you need. I did a quick calculation of a 1.050 OG wort and it calls for a half packet for a 2.5 gal batch. Once you get to ~1.10 OG then we are talking a whole pack for 2.5 gal.

To answer the other part of your question, I would just toss the stuff you don't use. Convention says to not make a starter with dry yeast. I personally have no experience with doing so, but maybe someone else can chime in.

Hi,

I've been doing BIAB batches of around the same size for over a year now and I always throw in the whole pack of yeast. I reason that a double helping of yeast will get things going quicker and it's more trouble than it's worth to keep a half packet of yeast hanging around.

Use a pitching rate calculator in the same way you would for other batches.

It sounds like you are talking mostly about dry yeast. In that case, it isn't great to save an opened packet of yeast, unless you can use the remainder soon. If you vacuum-seal and refrigerate the opened pack, you buy yourself more time. A starter would be a great way to use the yeast efficiently. That way, you can pitch what you need and save the rest, either as slurry in the fridge or as frozen stocks.

There really isn't any "wrong" answer on this one.

Personally, I would keep it simple.

Toss in the entire packet without hydrating. You'll lose some cells, but you'll have more than enough to complete a nice, healthy fermentation. I drop half a packet (non-hydrated) of yeast into my 1 gallon batches and have had excellent results (no off-flavors from yeast stress).

There is nothing wrong with using dry yeast in a starter. It is rarely done b/c dry yeast has about 200 billion cells in each packet and a phenomenal shelf life (when compared to liquid yeast). Therefore, your yeast counts are generally high enough to pitch straight (after hydrating to ensure some viability). If your beer is HUGE, folks will pitch two packets b/c they're inexpensive.

Thanks guys! I was wondering if using too much yeast would be a problem. I will probably check with a calculator and go from there… or just toss in the whole pack.

I'm assuming there is really no difference in using dry, liquid or a smack pack - right?

aces-n-eights said:

I'm assuming there is really no difference in using dry, liquid or a smack pack - right?

Click to expand...

Assuming the same strain, the only difference is the cell counts and a small difference in lag time.

FirstAidBrewing said:

Assuming the same strain, the only difference is the cell counts and a small difference in lag time.

Click to expand...

Excellent, thanks again!