Harvesting cider yeast

[guypettigrew]

Over the last several months I've made a good few batches of Wobbly Gob Great Barr cider, which I really love.

Mostly I've used the dried yeast which comes with apple concentrate. Once, though, I used WLP775. An English cider yeast from Malt Miller. It significantly improved the cider, giving it a more 'appley' taste and generally more interest. The next one I made used the dried yeast again, just so I could compare. Very good with the dried yeast, but nowhere near as enjoyable as the wet yeast.

Another Great Barr cider kit has just started fermenting today, using WLP775.

How do I harvest it for future brews, please? I'm used to harvesting my WLP yeasts from beer to get 4 brews out of them. But the beers ferment much more quickly and vigorously. Thick krausen, loads of gas etc. I stir the brew up after 24-36 hours and scoop 1/2 litre out and store it in the 'fridge.

The cider yeasts are very slow and steady. No real krausen, not very much gas.

Should I still scoop some fermenting cider out, or should I wait until fermentation has finished and collect the yeast using the bottom valve on my conical fermenter?

Or is there some other well established way of collecting cider yeast for future use?

Thanks in advance.

Guy

[MashBag]

I am not a technical yeast harvester, there are more refined ways.

However I have had 100% success filling small plastic water bottles with the most active ferment and freezing it. I do 3 at a time.

Thaw & pour as required.

[guypettigrew]

I am not a technical yeast harvester, there are more refined ways.

However I have had 100% success filling small plastic water bottles with the most active ferment and freezing it. I do 3 at a time.

Thaw & pour as required.

This is a wind up, right?

As I understand it, yeast is killed by freezing unless steps are taken to prevent this. The walls rupture as it thaws out.

Seriously, do you just thaw it out and pour it into a new brew?

Guy

[Good Ed]

I've never done it, but I imagine it is the same as for splitting beer yeast and making up starters before use (plenty of info on here on both of these). However you would want to use a different medium, and I would suggest pasteurised apple juice instead of wort, otherwise the process should be the same.

PS you might want to dilute the apple juice with water to get a SG of around 1040.

[MashBag]

Serious (no smiley face - fact).
I have even been known to undo the cap and just drop the frozen bottle in.

Couple of thoughts.

Yeast survived an ice age.
Domestic freezing is not that cold typically -12c to -15c

I have "abused" freezers for a while now. If "how to get the most and more out of your freezer" was a beer comp I would be a medal holder.

[f00b4r]

The fact that domestic freezers can not go very low and fast is a negative thing. Freezing slowly means bigger ice crystals so likely more damage, this is also the reason why making ice cream using just a standard freezer results in “icey” ice cream (unless you use e.g. alcohol or stabilisers like carageen to prevent this). It is also why people use glycerin when freezing yeast at a homebrew level, it also prevents the formation of these crystals that rupture the yeast cell walls.
Professionally frozen yeast is considered to have a hugely different lifespan at -80C compared to -20C.

You might get away with freezing and thawing yeast like you would any other food but it is far from optimal and akin to denying that starters are a relevant tool to build cell numbers and/or get the yeast in better health.

[guypettigrew]

I've never done it, but I imagine it is the same as for splitting beer yeast and making up starters before use (plenty of info on here on both of these). However you would want to use a different medium, and I would suggest pasteurised apple juice instead of wort, otherwise the process should be the same.

PS you might want to dilute the apple juice with water to get a SG of around 1040.

Thanks Ed

I've just scooped 1/2 litre of actively fermenting cider into a jar which is now in the 'fridge. It'll be interesting to see how much yeast settles out as it finishes fermenting.

Good idea about using apple juice to make a starter. I use 'Growers' Harvest' apple juice from Tesco to prime the cider when it goes into a keg. I could also use it for the starter. It has 111g sugar per litre, which should give a gravity of about 1.040 without diluting, I think.

Guy

[MashBag]

You might get away with freezing and thawing yeast like you would any other food but it is far from optimal and akin to denying that starters are a relevant tool to build cell numbers and/or get the yeast in better health.

I agree, I also think it is a numbers thing. 500ml even after some damage is probably still has millions of viable cells.

Yeast in my experience is remarkably resilient.

Mr Gervin and I some years ago discussed red wine fermentation and I tested his theory that 10g would indeed ferment 400 litres.

[guypettigrew]

Hmmm, harvesting cider yeast is far more problematic than I'd expected.

The 500ml I scooped from the top has yielded the thinnest of layers of yeast on the bottom of the jar.

So I collected another 500ml from the bottom valve on my conical fermenter after the cider had been cooled to about 6 C ready for kegging.

Again, the thinnest of layers of yeast on the bottom of the jar.

Even if the jars were combined It's hard to believe there's enough yeast to grow up in a starter. And No, I don't want to go the 250ml, 500ml, 1 litre route. Too time consuming! I will try combining the yeast deposits and seeing if it's a goer in 1 litre of apple juice, but I don't hold out much hope.

The cider with the wet yeast (WLP 775) is definitely better tasting than with the dried using the dried yeast which comes with the kit--although that's good as well. But I don't want to have to buy a new sachet of yeast for every cider kit I make.

Any suggestions, anyone, please?

Thanks.

Guy

[Cobnut]

Guy,
Can you not innoculate some slants when you buy a new package of yeast?
This is my latest approach to growing my yeast bank.
I make a batch of blank slants and then innoculate a couple for each new yeast that I get.
Also quite a good way to "share" yeasts with fellow HB'ers.
Cobnut