When is the best time to split yeast?

[squirt in the turns]

When using liquid yeast - when is the best time to split into batches? E.g., some yeast is to be pitched, the rest stored. I guess answers will vary wildly depending on the strain, beer it's going into, etc.

I have a 5L starter of 2278 (Czech Pilsner) made from a whole smack pack, stepped up without splitting. It's now chilled to 2 degrees,I plan to siphon off the spent wort, split some into a couple of stubbies, and pitch the rest. Is this a good practice? How much should I collect in each stubbie?

Also have a smackpack of 1272 (All-American Ale) for an AIPA. I plan to make a starter, so should I split it when pitching, or as soon as I open it? Can/should 1272 be top-cropped (description doesn't say it's a top cropper)? Is top cropping best practice to just pitch, then split what's cropped later on?

Cheers.

[bullfrog]

Before the fridge that housed my yeast farm was killed by an idiot with a screwdriver, I used to split after building up in a starter. I'd build a 2 - 2.5L starter, chill, pour off beer, add a bit of sterile water to swirl up the yeasties with then split off into little plastic bottles. Was collecting probably about 100mL into each bottle and that's more than enough to build another starter off (if you start it nice and small then step it up.)

No idea if that's the best way but it sure is easy and I never had any troubles (well, except for when I'd first built my stir-plate and hadn't quite tested it properly before trying to use it to build a starter -- turned my erlenmeyer into a bloody blender!)

[warra48]

I save one or two test tubes from the slurry of my built up starters. The rest is pitched into the brew.
The test tube is used to build up another starter, first 0.5 litre, then onto 2.5 to 3 for ales. Gives me enough yeast for another batch. For lagers, I build it up once more, as I like to pitch a big volume of yeast into those.

Essentially, I do the same as bullfrog, except I don't have a stir plate. However, I aerate mine with an aquarium pump and an airstone over about a 6 to 10 hour period at each step. That's long enough to enable decent growth.

[squirt in the turns]

Thanks guys. I'll split at the end of the starter stage. I've got the 1272 firing up now and I won't try to top crop it.

I'm planning an English Bitter using 1187 (Ringwood Ale) in the next couple of weeks, so I'll have a go at top cropping then. I'm still a bit confused as to when's best to split top-cropping yeast for storage (as opposed to direct pitching); after building up from a starter, or harvesting from the krausen? Maybe I'll try both, and see how vigorously a starter from each method takes off later on.

[drsmurto]

Top cropping is a different beast altogether.

A few ways of going about it.

Some skim off the first 'dirty' krausen and then skim the 2nd clean krausen.

I wait until the dirty krausen drops and then skim just before FG is reached.

If storing you need to leave the lid on the container loose for a few days as this is extremely active yeast and will still ferment out even in a fridge. I have stored top cropped yeast for up to 2 months and when reusing it made the mistake once of making a starter. It climbed out of the flask in less than 30 mins (1L starter in a 3L flask) so i now repitch directly (although i wouldnt keep the yeast for more than 2 weeks before doing so).

After you skim you will notice a new krausen form. You can skim this too.

This is a picture of the result of 1 top crop. It settled down to a nice tight 100mL slurry of yeast which in this case as its only yeast is more than enough to repitch (if you were using yeastcake i would use 3 times that much as yeastcake contains a lot of other things other than yeast - proteins largely).

[squirt in the turns]

Thanks DrS. I'm still a liitle fuzzy on some points, though...

I have stored top cropped yeast for up to 2 months and when reusing it made the mistake once of making a starter. It climbed out of the flask in less than 30 mins (1L starter in a 3L flask) so i now repitch directly (although i wouldnt keep the yeast for more than 2 weeks before doing so).

So, if it was ready and eager after 2 months, what's the issue with storing it for longer than 2 weeks?

If I were to crop and end up with 100ml, but didn't want to directly re-pitch within a couple of weeks, could I split and store longer term (a few months) using the standard sterilised water technique? Or would I be better off splitting at the end of the initial starter phase?

[drsmurto]

I prefer not to store yeastcake or even top cropped yeast for more than a month. You can get away with it but you will need to build up the cell count again via a starter. The longer it sits the more cells die off and the greater the risk of the yeast going to funky town.

I figure that with short term storing of yeast the greater the turnover of yeast ie. the more fresh yeast i buy. At <$15 a smackpack/vial and with a minimum of 3 batches per pack/vial i am happy to buy more. I know that when i buy a pack/vial its fresh and viable, after it has been used and without a cytometer its nothing more than a guessing game.

That's how i approach this, no doubt there are a million other ways and I am not saying mine is right but it works for me.

[squirt in the turns]

Thanks again doc. I pitched a smack pack of 1272 into a 2L inital stage, poured off the beer and pitched about 3/4 of it into a batch of your JSGA clone. I then fed it another 2L, poured off and pitched 3/4 of that into an AIPA, splitting the rest into 3 stubbies and covering with sterile water. These have settled out to a few mm of sediment in each bottle.

When I come to use these, I would build them up in a couple of hundred ml, then up to 2L. I don't know when I'll be using them, though. As a general rule, as long as the starter ferments out and doesn't smell or taste weird, it's pretty much ok, right?

[drsmurto]

Sounds fine to me.