Author Topic: How much alcohol is dangerous for yeast during a starter  (Read 736 times)

Offline toohoppy?!

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How much alcohol is dangerous for yeast during a starter
« on: March 27, 2014, 03:27:44 AM »
As a new homebrewer, I have discovered that things don't always work out as expected.

I prepared a yeast starter according to John Palmer's book recommendation. Maybe through a deviation from his recommendation, I ended up with a OG of around 1.060, seemed high but I pitched the WP001 anyway and set on the stir plate for 24h. Now the sg is 1.037, so ABV around 3.0%

What is the max acceptable OG for a yeast starter?
What is the max acceptable ABV for a starter yeast, and can ABV be used as an indicator that the yeast remain in the growth phase during the starter, and not the fermentation phase?...and does it really matter?

Offline klickitat jim

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #1 on: March 27, 2014, 03:57:44 AM »
The maximum allowed starter gravity is 1.035. Anything higher is forbidden. You must apologize to the forum and promise to never do it again.

Offline klickitat jim

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #2 on: March 27, 2014, 03:58:50 AM »
FYI, when I make a high gravity beer I use a 1.050 five gallon hopped starter.

Offline majorvices

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #3 on: March 27, 2014, 11:30:28 AM »
First off  your starter will be fine. Optimal starter worts are between 1.015 and 1.035/40ish. But your starter should be fine. You will find yeast are extremely resilient. And a 1.060 starter is 10xs better than no starter at all!

Offline duboman

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #4 on: March 27, 2014, 12:28:11 PM »
Yeah, the starter will be fine. In the future get a scale and weigh out the DME, it's more precise.

I use a 10:1 ratio meaning 100 grams extract to 1L of water and so on. This will always yield a starter wort of 1.035-1.040 which is perfect. If you are dealing with old yeast or building up from dregs then use a bit less DME like 5:1 or 7:1
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Offline HoosierBrew

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #5 on: March 27, 2014, 12:32:27 PM »
And a 1.060 starter is 10xs better than no starter at all!


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Offline Jimmy K

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #6 on: March 27, 2014, 12:46:43 PM »
Yeast will remain in growth phase as long as oxygen is available. On a stir plate, that will be until the starter is done.
Also, aerobic yeast metabolism breaks sugar down into CO2 and water. Yeast only start fermentation and produce alcohol after oxygen is depleted. This means a properly aerated starter will contain no alcohol when finished. It's the sugar concentration at the beginning that stresses yeast in a starter. But don't worry, you're starter will be fine.
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Offline a10t2

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Re: How much alcohol is dangerous for yeast during a starter
« Reply #7 on: March 27, 2014, 03:00:25 PM »
That's an error in HTB. Where it says a pint of water, it should say a quart.

What is the max acceptable ABV for a starter yeast, and can ABV be used as an indicator that the yeast remain in the growth phase during the starter, and not the fermentation phase?...and does it really matter?

In any real wort (over about 1.004 SG), the yeast will be able to utilize both aerobic and anaerobic metabolites, assuming they have access to oxygen. There's really nothing practical you can do at the brewery level to prevent fermentation while propagating. The yeast banks do it by keeping the SG below 1.004 and continuously dosing in additional extract.
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