First brew complete! Quick question.

So my first brew (2.5 gal black IPA with specialty grains) went perfect. Lots of research here helped! Everything is going well (OG was 1.069, called for 1.075) and fermentation started around 12-15hr mark. I have a climate controlled mini fridge and have been able to keep the fermenting to 63-64 degrees. In my limited knowledge of us-05 yeast that seemed perfect. Well checked on it last night and it was 64, woke up and checked and it had gone up to 69 degrees. I understand fermentation causes heat, but it seemed to jump quickly and caught me off guard overnight. I have since adj my ambient temps to bring it down to 64 again but will the higher fermenting temp for that short time give a lot of off flavors?

PS: Fermentation is exciting your first homebrew

The heat during fermentation jumps extremely quickly, it's because this heat is actually being produced by the wort/beer, so it doesn't take the time to warm up like something that is absorbing ambient heat. The energy is coming from each cell of yeast in suspension, that makes for a lot of surface area and very efficient heat transfer.

This small jump is nothing... A lot of people don't realize how much energy is given off by the yeast and their beer jumps to 80dF without them even realizing, you'll most likely turn out excellent beer. Most off flavors will get cleaned up (reabsorbed) by the yeast over time, it's why on here we typically suggest longer fermentations than the kits tell you.

But seriously 69dF is nothing at all to worry about... RDWHAHB, and congrats on the first batch

69 isn't even really in the range of off-flavors even if you left it there the entire time. Neither is 70 for that matter - 71 - eh, 72 not great, etc...


Since you already have a fridge, I advise you to invest in a temp controller with a probe - either build one or buy one. That way, with your probe taped to the side of the fermenter, when the temp of the beer starts to rise, the controller will adjust the fridge temp down, etc.

Actually, you said you have a "climate controlled mini fridge," which does suggest a temp controller may already be set up. If you do have such a setup, where's your probe?

One thing that's very helpful in such setups, that a lot of us do, is to take the probe, a hunk of bubble wrap, and some packing tape, and attach the probe directly to the side of the fermenter. The bubble wrap acts as a insulating layer between the probe and the ambient air, so the probe is touching the fermenter on one side and the bubble wrap on the other side. This way, you're not constantly manually adjusting ambient temps; instead, your controller is monitoring your fermenter temp for you!

Thanks guys, glad to know all is good!

J187 said:

Since you already have a fridge, I advise you to invest in a temp controller with a probe - either build one or buy one. That way, with your probe taped to the side of the fermenter, when the temp of the beer starts to rise, the controller will adjust the fridge temp down, etc.

Click to expand...

The mini fridge has a 2 stage temp controller for heating and cooling. However the probe is setup for ambient temps. I'll have to look into making a setup that can control fermentation temps. Maybe do what you mentioned and tape or attach somehow and then insulate from the ambient air etc.

stratslinger said:

Actually, you said you have a "climate controlled mini fridge," which does suggest a temp controller may already be set up. If you do have such a setup, where's your probe?

One thing that's very helpful in such setups, that a lot of us do, is to take the probe, a hunk of bubble wrap, and some packing tape, and attach the probe directly to the side of the fermenter. The bubble wrap acts as a insulating layer between the probe and the ambient air, so the probe is touching the fermenter on one side and the bubble wrap on the other side. This way, you're not constantly manually adjusting ambient temps; instead, your controller is monitoring your fermenter temp for you!

Click to expand...

Bubble wrap is a great idea! I can get long food grade temp probes through my work. Another option would be to insert a sanitized probe directly into the wort through a sealed grommet on the top of plastic better bottle. The seal would be above wort level to reduce risk of leaks but the probe would extend into the wort. I think keeping it simple (less chance of infection) with the tape and bubble wrap is on the board for next brew! Hell think I might go tape it on today!

Yeah, I've definitely considered the thermocouple method (there's a couple commercial solutions available, that basically amount to hollow stainless steel tubes that you submerge in your wort, and you place your probe inside those tubes), but taping the probe to the fermenter has been working well for me for the past year+ since I put together my fermentation chamber, so I'm good with it. KISS method and all that.

If you don't want to bother with tape and bubble wrap, you can also use an ace bandage. Holds the probe snugly against the fermenter, with no need to re-tape each time...

Bubble wrap works, but it's not the best way, get or make a stopper with a thermowell for a probe in the center of the wort, that's where the temp will be the highest and you'll get most of your off flavors.