I'm currently brewing 1 gallon batches. Say I have a liquid yeast smack pack that's for a 5 gallon batch. What I'd like to do is use about 1/4 to 1/3 of the pack and store the rest for later brews.

I've read all about how you can store yeast slurry from a previous fermentation, but I'm not convinced the process is the same for yeast straight out of a pack. For example, the nutrients will vary greatly between plain yeast and yeast plus trub. Also, the yeast is at different stages of activity in these two situations.

What I've thought of so far is to pour the remaining yeast into (sanitized) mason jars with pre-boiled water, but I'm worried this won't be enough to keep the yeast alive in my fridge for long. On the other hand, I don't want to feed my yeast with DME, or something similar, and have a bunch of brewer's fireworks go off in the middle of the night.

Does anyone have a practical solution for saving yeast directly from a smack pack or yeast packet?

3 Answers 3


There is so little yeast in one of those packs that you'll have a really difficult time dividing it properly. You need to make a starter for any beer over 1.040 OG (despite what the yeast companies would have you believe). You ask if there's a practical solution and there really isn't a good way to do what you want to do. You could make a starter and save part of that. That's about the best you can do.


According to Mr Malty, you'd need about 1/3 of a pack for 1 gallon at 1.048 for direct pitching. The yeast will only remain highly viable for 2-4 weeks, though I've certainly pitched 6 month old washes that have functioned, though it was likely way under pitched.

I would recommend using Mr Malty to determine how much to pitch in your 1 gallon batch (which will vary by OG), and then do your best to measure the entire contents and save off the remainder (in a sanitized container). Ideally, you don't want to over (or under) pitch but you may have less viability for the next batch, so either use a small starter for batches 2 and 3 or pitch the 2/3 into the second batch.

In the end, the most practical solution is to brew at least 3 gallon, or preferably 5 gallon batches, since the bulk of the yeast, (and home brew equipment, materials, et al) are designed for 5 gallon batches.


You'd be better off saving the cake from the one gallon batch in small jars and reusing that.

Putting even half a smack pack into a normal sized mason jar will leave too much surface area and headspace for oxygen exposure. You need to minimize that to extend the livelihood of the yeast.

If you wanted to invest in some pipetting equipment and some small tubes then I think you'd be in business. But aside from that the volumes you are trying to work with won't treat your left over yeast well.

Dry yeast may be a better option as well.

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