fermentation too hot?

[hoox]

This would have been asked countless times already.

I have completed two BIAB brews both which have two 'high alcohol tastes'.

The first tastes like this after having 5 weeks conditioning (nz epic pale ale clone), the other I bottled this morning (american IPA) and has the exact same taste.

The first batch I put down to having fermentation at a high temp. Had a crazy 3 days of 26 degree temps and had no temp control.

By the time I got onto the second batch I had purchased a Fridge and made a temp controller so that I could ensure a 18-20 degree ambient temp.

However I think I've been naive and assumed that all temps stated were ambient temps. After reading around it seems that the heat generated from fermenting should be considered and I should cool appropriately. But even then say it was at 24-25 degrees (and I never checked so cannot be sure) would this be enough to produce 'high alcohol' flavors? (US-05)

I guess the answer is that I should apply the temp sensor to the fermentation barrel instead of ambient?

Also, when trying to cool the wort I assume that is there no harm in leaving it in the fridge until I pitch my pitch temp? even if it takes 1/2 a day? Cause when I use my wort chiller I find it gets to ~30 degrees OK but any lower takes a bit of time (water out of tap is ~16degs).

For the second batch I used Safale US-05 and re-hydrated with 27 degree 120ml for 20min and stirred for 15min then pitched. I was going to chuck it in dry as it says ok on the packet but I have OCD etc, probably like most peeps here.

 

[pharaohpierre]

The issue with there being an unwanted alcohol flavor in your beer I don't believe has to do with the fermentation temperature, even though you are having an issue that needs to be adjusted. Yeast can produce undesirable flavors if fermenting outside suggested temperature ranges. However, I think the issue lies somewhere else.

What temperature were you mashing at. What is you OG and FG, your attenuation rate? Are you overboiling and concentrating the wort? Tell us more about this American IPA recipe and your numbers.

 

[MindenMan]

Yes, high temperature ferments cause fusel alcohols to form. Hot, burning kind of sensation. The beer is still drinkable, but be careful of hangovers.
The only thing about not cooling your wort quickly is, it changes hop character/flavor. Taking overnight to get to pitching temperature, won't ruin anything, your beer will be happy to ferment at a lower temp, and provide much better beer. If you can keep your fermentation temperature right at 18 *C for a week or so, then gradually raise the temperature up day by day to help chase off any hot or other types of unpleasant alcohol flavors. If given the opportunity I would raise the temperatures of my 2 batches a degree or so every day until the funny flavors have left the building.

 

[RM-MN]

This would have been asked countless times already.

I have completed two BIAB brews both which have two 'high alcohol tastes'.

The first tastes like this after having 5 weeks conditioning (nz epic pale ale clone), the other I bottled this morning (american IPA) and has the exact same taste.

The first batch I put down to having fermentation at a high temp. Had a crazy 3 days of 26 degree temps and had no temp control.

By the time I got onto the second batch I had purchased a Fridge and made a temp controller so that I could ensure a 18-20 degree ambient temp.

However I think I've been naive and assumed that all temps stated were ambient temps. After reading around it seems that the heat generated from fermenting should be considered and I should cool appropriately. But even then say it was at 24-25 degrees (and I never checked so cannot be sure) would this be enough to produce 'high alcohol' flavors? (US-05)

I guess the answer is that I should apply the temp sensor to the fermentation barrel instead of ambient?

Also, when trying to cool the wort I assume that is there no harm in leaving it in the fridge until I pitch my pitch temp? even if it takes 1/2 a day? Cause when I use my wort chiller I find it gets to ~30 degrees OK but any lower takes a bit of time (water out of tap is ~16degs).

For the second batch I used Safale US-05 and re-hydrated with 27 degree 120ml for 20min and stirred for 15min then pitched. I was going to chuck it in dry as it says ok on the packet but I have OCD etc, probably like most peeps here.

You definitely should control the wort temp instead of the ambient temp as the activity of the yeast will increase the temperature during the ferment. I don't have the active control but I have my fermenter where it is cooler and have measured about a 2 degree temperature difference. If it were in a warmer location, the yeast become more active which will raise the temperature more. Then because the temperature is warmer, they get more active yet.

Chilling your wort to 30 and them putting it into the fermenetation chamber is a good idea. If you put the controller sensor taped onto the fermenter with a bit of insulation over it the wort will chill faster than you think because the refrigeration unit will work harder to make the wort chill. The temperature inside the refrigerator will be much colder than the 18 to 20 C. as it tries to chill the wort. Check the wort temp in about 4 hours and see if it isn't near pitching temp.

 

[Newsman]

Another thing you can do is get another immersion chiller and stick it in a bucket of ice water and then run that through your regular chiller as a "pre-chiller." That is what I'm planning on doing when it gets to be summer up here in the States as my water temp will probably be significantly warmer than it is now. I just made a batch of Dunkel on Wednesday and used my IC for the first time and I got down to pitching temps (or slightly lower) in about 10-15 minutes. I was running my IC full blast and stirring like crazy, and it worked!
Good luck figuring out your issue, but I'd say maybe the guys here asking about your mash temps may have a good point.

 

[BigFloyd]

However I think I've been naive and assumed that all temps stated were ambient temps. After reading around it seems that the heat generated from fermenting should be considered and I should cool appropriately. But even then say it was at 24-25 degrees (and I never checked so cannot be sure) would this be enough to produce 'high alcohol' flavors? (US-05)

I guess the answer is that I should apply the temp sensor to the fermentation barrel instead of ambient?

When using a controller like you now have, tape the sensor to the side of the fermenter and cover over it with some sort of insulation (I use bubble wrap). It's the beer temp that matters, not the air.

Also, when trying to cool the wort I assume that is there no harm in leaving it in the fridge until I pitch my pitch temp? even if it takes 1/2 a day? Cause when I use my wort chiller I find it gets to ~30 degrees OK but any lower takes a bit of time (water out of tap is ~16degs).

With 16*C tap water, you ought to be able to chill down to about 22*C no problem. Are you stirring the wort with a sanitized spoon while you chill? Stirring frequently really helps when chilling. It's fine to seal it up and put it in the chamber to finish. To shorten the wait, I set the chamber ahead of time for really cold (like 2*C), put the fermenter in and then reset the controller for the pitch temp I want (16*C for ales, 8*C for lagers). After it gets there and I pitch, I'll set the controller for the initial ferment temp.

 

[aiptasia]

There's two useful tools for using the temperature probe of your temperature controller on your fermentation chamber:

1) A Thermowell or
2) Duct Tape.

A thermowell is a metal tube that you can insert into your fermentation vessel (bucket, carboy, etc.) that will protect a temperature controlling probe from getting wet with the wort of your beer as it ferments. They will give you a very accurate fermentation temperature on your beer.

A piece of duct tape is just that, a way to tape the temperature probe directly to the outside of your fermentation vessel. This is the poor mans method and the one that I use. Just take a piece of tape and tape the temperature probe to the side of the bucket or carboy about 2/3rds of the way down the bucket. This works well for measuring the temperature of the actual beer and not the ambient temps as the beer ferments.

 

[hoox]

Thanks for all the feedback!


With regards to mashing: I've questioned myself on this too. I've learned a lot from my last two mashes and noticed hot spots (within the grain-bed) in the my last one where it was 68. 68 is too high and should be 64-66 AFAIK. I read somewhere not to disturb the grain-bed which lead to this increased temp. Next time I will be stirring occasionally, use less water during my mash so I can top up with hot water to increase temps if required.

Would too high mash temps cause increased alcohol taste? I've read that too high mash temps increase tannin extraction...in my mind this would give it a burnt woody taste?


With regards to cooling: OK my next brew I will stir the wort during cooling, which I haven't been doing cause I can see that the beer so really clear as soon as I chill and thought this might be a good thing...probably doesn't actually matter.

When people mention whirl-pooling is this after chilling to reduce the sediment during ferm?

 

[BigFloyd]

Would too high mash temps cause increased alcohol taste? I've read that too high mash temps increase tannin extraction...in my mind this would give it a burnt woody taste?

Higher mash temps give you more unfermentable sugars, leading to a more malty/sweeter profile. Lower mash temps provide more fermentables, thus producing a drier beer after ferment.

68*C is 154.4*F. That's not too high of a mash temp for many styles and is only slightly above average. I just did a maibock lager on my E-BIAB system (PID controlled) where the mash temp was, by design, 156*F (almost 70*C) for a more malty profile consistent for the style. You aren't going to see tannin extraction unless you exceed normal mash-out temps.

With regards to cooling: OK my next brew I will stir the wort during cooling, which I haven't been doing cause I can see that the beer so really clear as soon as I chill and thought this might be a good thing...probably doesn't actually matter.

When people mention whirl-pooling is this after chilling to reduce the sediment during ferm?

I've whirlpooled before. Now I just cover the kettle and let it sit for 15-20 minutes after chilling. That, plus using whirlfloc at 10 min left in the boil allows me to leave the gunk behind in the kettle.

 

[hoox]

OK so tonight I had my New Zealand Harrington's brew club and I asked the head brewer what he thought and he said first up check fermentation temps then mash temp...un/fortunately I will do both so if it comes out good then I will not know the real cause.

Had a Wiesenbock tonight, my first real estery tasting beer and what an experience this way! way diff to other beers I've had.

 

[BigFloyd]

OK so tonight I had my New Zealand Harrington's brew club and I asked the head brewer what he thought and he said first up check fermentation temps then mash temp...un/fortunately I will do both so if it comes out good then I will not know the real cause.

Had a Wiesenbock tonight, my first real estery tasting beer and what an experience this way! way diff to other beers I've had.

It's all good and you're gaining useful brew knowledge through this whole experience.

If you haven't already done it, check your thermometer in both boiling water and ice water. Also check it against other thermometers. I have a floater that's a full +7*F off.

 

[hoox]

...everyone likes a follow up.

Doing my third batch now...currently @ Day 4 of fermenting.

My second batch wasn't so bad and now I'm actually liking the beer very, very, much.

For my third batch, same recipe as second, I used way less water to mash so I could get better temp readings. This helped A LOT, especially finding hot spots of grain sitting there and I could then do a little stir to even it out ~65. I never used the gas hobs after adding grain and just used hot water to top up now and then.

While boiling I did a taste test every 10 minutes to see when the 'bad taste' comes in...if it were to come in on this batch. I figured the hops bitter started to kick in around the 35min mark. I think my first batch, which tasted like alcohol, was perhaps from having too much hops for too long as I may have let it boil a little too long and thus subsequent flavoring hops amped up the bitterness to make it taste like additional alcohols.

I placed the fermentor in the fridge to get down to a solid 18.5 degrees then added the re-hydrated yeast. I got an overflow in the airlock, which I haven't had before, gave it a clean and put it back on. I'm not worried about it, actually I'm thinking that it might be a good sign.

 

[Newsman]

Hoox... you should seriously consider a blowoff tube if you're having blowoff.

 

[zdbrown1]

I always use blow off tubes just to be safe

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