Yeast harvesting from trub

[UKSkydiver]

Hi all.
I rinsed and harvested my yeast from FV (first time) today.

It was a small-ish 8 litre batch that I put a packet of S-04 into.

I have a couple of questions:

1 - I mistakenly used a fresh, previously unopened bottle of Ashbeck instead of distilled water (or cooled, boiled water) - Does it matter?
2 - Given the amount I have currently settling since this morning, (about 6mm in the bottom of a sterilised jam jar) and assuming I didn't completely cock it up using Ashbeck above, how much should I expect to use in the next brew. I only generally do 8-10 litre batches. All or half or something else?

Or to put it another way, when yeasties are doing their thing in the FV - do they multiply?

Hope that makes sense.
Cheers

 

[MyQul]

Q1 I never rinse yeast so Im not sure.

Q2 How big is that jar. If it's say the size of a robinsons jam Jar. If I had that much yeast I'd put it in a 600ml starter for my 10L brews . I'd only use that much if that jar is the size of a demijon

 

[cushyno]

Going off the rule of thumb I have used, about 250ml of trub is about a third of the total trub from 23L batch. This is enough for my next batch if I repitch within a couple of days. You'll collect let than that by the time you've rinsed.

I imagine that this scales to any size of vessel. If you collected all of the yeast from your FV, use 1/3 if it in the same sized FV next time.

Questions to ask yourself:

• Did I lose any yeast during collection or rinsing?
• Was my yeast stressed during the last batch?
• Am I going to store the yeast a while before repitch?

If any of these are answered "yes" then you'll need to increase above the 1/3.

 

[terrym]

Recent thread about this here
https://www.thehomebrewforum.co.uk/threads/trub-yeast-re-use.85651/Today I spooned out about three quarters of a pint of trub from a completed brew into a pint glass (both sanitised of course), then covered glass with cling film and put it in the fridge. In two days time I will take the top quarter or so of that and pitch it into my next brew. I often do that way. But I won't keep the trub for any longer than two weeks, after that it gets chucked. For me its as simple as that.

 

[foxy]

I don't know about Ashbeck water or if its sterile, yeast starts to starve if you don't feed it. According to Chris White the viability drops by 50% over a week stored at 4 C, if you are not using it straight away and storing it then make a starter. You can feed the yeast (much like you do sourdough yeast ) but it isn't worth the effort or risk.

Discard the froth at the top, and keep the creamy bit in the middle, the dead yeast is the darker brown at the bottom.
The yeast will multiply as soon as it starts to feed in the wort and aerate the wort beforehand,
depending on the freshness of the pitched yeast is also a factor of how much you use.

 

[UKSkydiver]

Firstly - I wanted to say thanks for all your replies. I've been thinking all week how to reply and I just end up coming up with a load more questions. I think the mixture of replies shows that there are more ways than one to this and the breadth of replies has confused me more. I think it has highlighted my lack of sufficient knowledge on yeast starters.

My question was really about re-using the yeast 'as-is' and not anything to do with making starters, for now.

So if I may, can I ask some more questions?

Given that I used a full 11g pack of dry yeast on a small 8 litre batch:
- how much would that likely have multiplied to? One and half times? Two times? Eight?
or, to put it another way:
- is there likely more in the jar now, than the original amount I pitched?
- or less?

The yeast won't have been stressed in terms of temperature (controlled at 18 degrees), pitch rate (less than half of a 'normal' batch) and alcohol level (a 4% ale)

If there is more than originally pitched, then surely I don't need a starter - I could just re-pitch, in which case, how much?


And for yeast starters (and I think that a lot of the answer will be "it depends") - how much would you typically expect yeast to increase by? Again, twice? More? I guess it depends on how much wort / temp / oxygen / time you feed it?

Thank you for bearing with me whilst I try and understand the next thing I need to understand!


** I think that for this actual jar of yeast, it's academic, as it's in non sterile water, we're nearly a week on and I don't have the skills or the kit to do a starter, but if I can understand how much it multiplies by, then it gives me a rough idea.

 

[UKSkydiver]

Q2 How big is that jar. If it's say the size of a robinsons jam Jar.

Yes - standard 400g/400ml-ish jam jar

 

[MyQul]

Yes - standard 400g/400ml-ish jam jar

Stick it in a starter to make sure

 

[Ben Matthews]

I use a free app on my phone called captain brew I think it is? It has really easy to use calculators on there for working out how much viable yeast you have. Just need to know roughly how many ml of yeast slurry is in the bottom of your jar,. How much of that is trub percentage wise, date you harvested it.

It then can tell you how much yeast you will need for your next batch based on batch size, style, OG and if you need more than you have it will tell you how big a starter you need to make to achieve that amount and how much DME to use etc. I would try and make double what you need for your next batch and then pour 50% into your beer and then you've got 50% extra you can just put straight in the fridge without the ball ache of washing yeast from the fermenter each time.

 

[UKSkydiver]

I use a free app on my phone called captain brew.

I did not know. I will take a look. Hopefully it will answer many of the Q?s I have. Cheers.