Help with a starter for larger batches

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Thirsty
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Help with a starter for larger batches

Post by Thirsty » Mon Jun 18, 2018 11:13 am

Hi.

I'm looking for advice on making a started for a 30G ~6.9% beer from a washed and saved yeast that is about 3-4 months old.

I have successfully washed yeast and reused it in a 1.5L starter for a 5G 5% beer before so I kinda sorta know what I'm doing but I'm just a bit worried about under pitching 30 gallons of beer.

Specifically, I'm wondering how many of my washed samples to start with. I have 4. 2 each saved from a 5G batch. I'm thinking I can start from 1 and build from there?

How old is too old for saved yeast?
How do I estimate starting cells? The online calculators seem geared towards liquid yeast packs and let me enter a packaging date. Should I assume one of my washed and saved containers is equal to a package of store bought liquid yeast (of similar age)?
What sort of containers do you guys use? I can start in my usual 2L flask that fits on my stir plate but after that it seems like it will outgrow the container quickly after stepping it up. Can I use a 5G carboy?

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oceanic_brew
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Re: Help with a starter for larger batches

Post by oceanic_brew » Mon Jun 18, 2018 3:26 pm

I’m gonna take a stab at this but there’s a lot going on here and I’ll likely miss the mark in a few areas.

First of all the health of the yeast slurry that you’ve been saving is dependent on many factors and will not hold up as well as purchased yeast from WL or Wyeast.

Second if it’s yeast slurry and not washed yeast it gets a little more complicated. There’s more dead cells In Slurry than in washed yeast not to mention other organic matter. That all being mentioned you most likely still have viable yeast cells.

You would have to estimate your cell count based on your harvesting practice and then for 4 months I would safely say you could be at 50% viability or less.

If you are set on keeping this yeast then follow your normal practices, figure how much of your harvested yeast gets you close to 100 billion living cells pitch into a 2 L flask on a stir plate and then brew a 5 Gallon beer with it. Probably one that’s around 1.040-1.055 OG and Use the yeast cake from that (probably not all of it) to brew the 30 Gallon Batch.

You’ll get a number of benefits here: you use your yeast you want, you proof it’s health and build up plenty of healthy cells by making a starter, and then you get 5 gallons of beer from it.

It’s cheaper to just buy yeast. Might even be cheaper to buy a 5L flask and a vial of yeast if your stir plate can handle it.


I won’t get into it here but for the fun of it look up how breweries build up yeast from 1 BBl pitches to 15 BBl with multiple wort additions.



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Woody
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Re: Help with a starter for larger batches

Post by Woody » Mon Jun 18, 2018 7:42 pm

I'm a huge fan of this yeast pitch calculator and it will answer some of the questions you have.

http://www.brewunited.com/yeast_calculator.php

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