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Yeast activity/ temperature question

Hello everyone, I used to brew beer quite a bit when I lived in a warmer climate (Florida), and now I live in a cooler climate (Tennessee). When I was in Florida, I could never get the primary to cool down below 70 degrees farenheit by having wet fabric around the bucket and a fan. The beers always turned out well, though.
So this week, I brewed my first beer in 6 years and am feeling rusty. I boiled the NB Megalodon Imperial Red Ale (extract).
I have a couple of concerns. Since it was a strong wort, I boiled about 600 mls of wort in a flask & used the liquid yeast to ferment & make a very small starter. The boil was put off a couple of days later than I originally planned, so I brewed 3 days after I began the starter. I also had an envelope of dry yeast. I threw them both in once I cooled the Megalodon down to about 66 degrees. It started bubbling the next day (yesterday) - about 30 bubbles a minute. Last night & today it increased to 67 bubbles a minute (in the 3 piece airlock). I got a blow-off tube ready to put on it once it became too vigorous, but it hasn’t been too vigorous yet. I don’t know if that is due to my 65-68 degree wort, or if I have a yeast problem. What do you folks think?

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No problem it sounds good to me

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You clearly have fermentation, and strong by the sounds of it. Just because you don’t have blowoff doesn’t mean there’s a problem. In fact, often when you have blowoff you’re fermenting too warm.


Thanks for that, I am so accustomed to the blow-off tube with higher gravities that I was worried my yeast was about to go to sleep. I appreciate it!

A reply but in a rush. Hope this generates some questions.

The bubble count seems quite high compared to my bubble counts through the air lock on sealed carboys. Are you monitoring the actual fermentation temperature or going by ambient temperature? Fermentation temperature will always be higher than the ambient. Same as us, yeast produces heat when doing hard work.

Sorry for being rushed. If nothings sounds right ask what I meant.


Thanks, @flars - I wish I would have been aware of kviek & scandinavian farmhouse yeast when I was in a warmer climate. I will remember that next summer.
I also didn’t know how long the starter yeast would be viable so that clarification helps a bunch.
I am using the thermometer “sticker” that is on the outside of my plastic Ale Pail. It is running around 68 & sometimes lately has been moving to 70.

Those temps are okay. Starting to get into the “warm” zone. However, temp control is the most important for the first 36-48 hours of actual fermentation. Increasing temps towards the end can promote full attenuation. So I think your fine.


Good to know. I have been opening a window (it’s in the 30’s outside) and running a fan. Probably not affecting much, but just trying to keep it under 70. I wasn’t worried enough to stick it in a cold water trough or anything yet. Sounds like it may work out okay.

This is the set up I use to keep the fermentation temperature controlled. The fan is often only needed for the first couple of days when the fermentation is most active.

I can use an aquarium heater controlled with a STC-1000 to heat the water bath to hold a steady warmer temperature.


That’s smart thinking, @flars. #redneckingenuity
I used to soak a polo shirt, stick it in the freezer for awhile, then my glass carboy would wear it while a fan blew on it. I’ve never had the tub though. I need to get one. My son has an aquarium heater. Maybe he won’t notice if it temporarily comes up missing.

The aquarium heaters I use have a set temperature of 75°F. I have never fermented that high with a yeast but do finish some ales and a saison at 70°F. The DIY STC-1000 control box is a cheap way to go for heating and cooling. I’ve set up one control box to be able to control two heaters at the same temperature.

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That’s really cool. They’re cheap…under $20 on Amazon! Thanks for the tip. I would not have known how to look for something like that.

Pictures of the STC-1000 in Getting Started category. Added a toggle switch so I could heat with both sides of the outlet. I’ll add another switch to reconnect the cooling relay to run the fan. Have a second unit with just heat and cool.

Check out the Beer Gear and DIY categories also.

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