Using an old cake

[Mr Fro]

Hello again everyone.

I've got a brew on at the mo which is due to finish up next weekend. Because I'm fiddling with recipes I'm only doing small batches (~10L) and I'm planning on getting another brew on straight away that's a very similar style as the current one.

I'm thinking of getting the new batch ready, bottling the current one while waiting for the new to cool, then dumping the new one straight on the existing cake.

Does this sound reasonable? Can anyone foresee any reason not to do this?

Also, to aerate, should I give it a good swooshing in the brew pan or can I do it in the FV with the yeast (preferred)?

Cheers,
Fro

 

[Slid]

It has certainly been done before! You won't need all that yeast, though, and there are said to be downsides to "over-pitching". These include over-attenuation, which makes for stronger, but thinner tasting beer. If you were to chuck away 3/4 of the cake and just use the other 1/4, this would be similar to my standard practice, which works fine for me.

 

[Cwrw666]

I always use a few spoonfuls of the trub from the previous brew stirred into the chilled wort of the new one - this lets me sanitise the FV of the new brew and in fact let the brew no-chill down to pitching temperature in the FV.

 

[beertrap]

I will reuse the yeast cake on any beer providing the first beer is 6 abv or less.

I make 5-6 gallon batches so after raking the first beer to the bottleing bucket I mix up the cake, store 1 pint of slurry in a sanitized pint swing top bottle then pour in the wort. Usually very fast ferment and I have yeast for another batch. The pint of stored slurry stays in the fridge.

 

[Mr Fro]

Thanks for the replies.

The general consensus is don't use it all then!

Keeping a bit back in the fridge sounds like an interesting option... What's the general idea - mix up the cake with the dregs of the previous brew then stick it in a jar/similar?

Thinking as I type; would this not preferentially select the more flocculant strains of the population?

 

[beertrap]

Yep, just be sure to have a clean sanitized container.

 

[beertrap]

Not sure on on the strains.
I use dry yeast so Nottingham, Windsor, muntons, many of the safe ale types store well.

It's not a good idea ,in my experience, to save yeast from big beers like over 8 abv. In the past using that yeast gave me sluggish ferments.

If one plans on brewing a big beer in the future, like a Russian imperial, I will make a Irish stout first, then use the entire cake for the rIS wort.

Be advised that the ferment will be explosive so a blowoff tube or splitting the RIS batch into 2 fermenters is advisable to avoid a big mess.

One time i did it and painted the ceiling of my cellar with wort, yeast ,,,, try getting away with that with the wife, hahaha.

 

[AdeDunn]

It has certainly been done before! You won't need all that yeast, though, and there are said to be downsides to "over-pitching". These include over-attenuation, which makes for stronger, but thinner tasting beer. If you were to chuck away 3/4 of the cake and just use the other 1/4, this would be similar to my standard practice, which works fine for me.

The one time I did it, that's pretty much what I did.

I used some of the cake from a fuggles hopped golden ale to brew a goldings and fuggles hopped bitter. Purely to save me the need to buy more yeast, allowing me to brew the second beer sooner. Attenuation on the first beer was 76.6% apparent, the second beer though hit 79.4% apparent attenuation... So yeah, be very careful how much of the old cake you pitch. If I remember correctly, I used about 1/2, which in hind sight was just a bit too much as they both had a similar OG.

I used a fresh, clean and sanitised FV for the second brew. Pitching the recovered yeast cake into the wort once transferred. I kept the cake under a thin layer of the previous beer until I was ready to use it.

I'm using Kveik these days, where saving the slurry is a common occurrence, but you use about 10-20mls of it per brew....

 

[Mr Fro]

Right, gotcha.

I'm brewing around 5% just now so sounds like it should be fine. I'm also using a 25L bucket for a 10-12L brew so plenty of head space.

If I remember, I'll take a sample of yeast suspension to work and chuck it on a cell counter to check viability/cell count/ etc.

Thanks to everyone for the help!