So, as I order ingredients for my next brew I have come across a question. If I am only doing a 2.5 gallon brew of a 5 gallon recipe, do I need to try and figure out a way to cut the yeast in half as well? If so, do I pour it into a small cup and weigh it and cut the weight in half? Or, can I just pour the whole packet in and let it go from there? Thanks in advance guys, I am hoping to do this over the weekend. RR
Here’s what I do.
Feel the pack before you pour it. Pitch about half into your brew based on feel. Fold the corner over and tape it. Put it back into your refrigerator.
Some folks don’t get wrapped around the axle about pitch rate and use the ‘one pack a batch method’. However, most dry yeast manufacturers suggest using weight to calculate cell count.
I use the Lallemand pitch rate calculator for their yeast products (Bry-97 most often) because it takes volume, temperature, and gravity into consideration… or the Fermentis general rule of .5-.8 grams per liter for Ales and .8-1 gram per liter for Lagers.
A quick rule of thumb for pitching rate is 6.5 grams of Ale yeast or 13 grams of Lager yeast per gravity point divided by 25 in a 5.5 gal batch. (6 and 12 per 25 points in 5 gal). (Gravity points / 25)*6.5 or 13 = pitch rate in grams. I would halve that in a 2.5 gal batch.
I store my yeast vacuum sealed in the refrigerator. Lallemand states that if the yeast is resealed under vacuum and stored cold it can be expected to be viable until it’s expiration date (2 years from mfr).
I have found it is viable beyond the expiration date. I have been using the same brick of Bry-97 I bought in Apr ‘20 with an expiration of Apr ‘21 without noticing any degraded performance. YMMV
In White and Zainasheff’s “Yeast” (Brewer’s Publications) they give pitching rate calculations based on cell counts, leaving the cells per gram (taking into account viability) up to the reader (pg 123).
I like the Lallemand calculator way better.
Wish I could go back to those heady days of just ripping open the packet and tossing it in. But I have looked into the abyss of pitching rate calculations and come away changed.
Awesome. thank you. I will see what I can figure out with the liquid yeast. I guess I can pour it in a bowl and measure it that way, right? Then either make the starter or put it in the wort.
I brew 3 gallon batches (fermenter volume) all the time and always use the full pack of yeast (dry or liquid). Is this “overpitching” the optimum method of yeast handling? Probably not. But it’s brainless and I’m not about to concern myself with storing open packs. I haven’t yet had a problem (that I’m aware of). I will acknowledge that there are some beer styles that might benefit from a more appropriate pitch rate (Hefeweizen?), but that’s probably a topic for another thread.
Thank you for the reply. If I use dry yeast, which I will in one of the two I am going to do, I will try and measure. If I use liquid, which I have yet to order because MoreBeer is out of it, I might just dump the whole thing in and see what happens. These two are more experimental brews.
I brew three gallon batches and throw in the entire pack for ales; two packs for lagers.
I also use Muntons 6 gram packs for bitters and milds.
There are many things in homebrewing that are not as cut and dry as it would seem. Pitch rate is one of those.
For 2.5-3 gallons of wort I’ll pitch 1/2 pack and save (vacuum sealed) the balance to brew another small batch if I’m planning on brewing again soon. If I’m not going to brew another beer soon I’ll just pitch the whole pack in.
Don’t mess around with trying to measure half of a pack of yeast. Just pitch it all. Making beer should be fun so don’t stress over things that may not make any difference.
I agree. I have measured half a pack a couple of times. It makes me paranoid that I might be contaminating the yeast.
Cell count has been published many times with wide variations, so I don’t try to get exact about it. I’d use the whole packet.
Pitch rate is obviously not an exact science, and is also another variable we can use to manipulate the outcome. But I choose to simplify my processes, and using the Lallemand pitch rate calculator is one of those, when I use dry yeast. I weigh it onto a piece of aluminium foil and reseal the pack. Not best practice, I’m sure, but it works for me.
If you have a clean disposable plastic cup fresh out of the package and a gram scale you can measure in that and pour it into your fermenter without any sanitation concerns. Then tape the packet shut for further use.
One use plastic. A small piece of foil does the job.
I like the way you think. However, the plastic cup can be used many, many times over. Hops. sanitizer. Drinking. Doesn’t have to be “one use”. Just sayin’.
Oh yeah sure. I just wouldn’t buy plastic cups in the first place tbh. It’s bringing yet more plastic into the world. I think we need to eradicate as much as possible.