Inverted airlock!

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abdominousabel

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Disclaimer: I’m buzzin’

This is hilarious! I put my yeast starter with an airlock in my chest freezer to cool down from 85 deg F (yikes) and now it’s at 77ish. The change in temperature caused a negative pressure in my erlenmeyer Flask! The airlock is now sucking in Oxygen! I find this hilarious and I don’t know why. Probably because it’s basic Ideal Gas Law and I didn’t think about it (obviously ) but after about 1min on the stir plate it’s back to normal, pushing out CO2. I’m sure the Oxygen is nothing to worry about since the few oxygen bubbles will probably feed the yeast rather than produce off flavors.

Happy brewing! Cheers!
 

GPP33

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One the main benefits of putting it on a stir plate is to feed the yeast plenty of oxygen. You may want to reconsider using the air lock, I think most people just put some foil over it so the CO2 can escape and the O2 can come in.
 

isomerization

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I will also add that yeast growth (for most strains) is optimal at 30C (86F), so no need to cool your starter.
 

myndflyte

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That's why you don't cold crash when you have a blow off tube hooked up and dipped in starsan. It's a good way to get a half gallon of starsan sucked back into your beer.
 
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abdominousabel

abdominousabel

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That's why you don't cold crash when you have a blow off tube hooked up and dipped in starsan. It's a good way to get a half gallon of starsan sucked back into your beer.
Wow I didn’t put two and two together, I cold crashed last batch like that and didn’t pay attention to that.. that more than likely happened. Do you just cap the carboy?
 
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