Stuck fermentation prevention

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Greynolds16

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Hey everyone,

It finally happened! Two years in and I am about to dump my first batch and I’d love to prevent this from happening again. If anyone has tips on what to change I’d love to hear them.

This was a kolsch 5 gallon batch, first ever on my new claw hammer system. 1.050 OG with a tilt hydrometer to give me gravity readings. Fermentation seemed totally normal (even a bit faster than my old system because the plate chiller helped with aeration) until it stalled at day 2 with a gravity of 1.028 where it has stayed.

My attempts to restart included letting it warm a bit - my cooling system is a big freezer bag that I put frozen two liters into for temp control - so I held off on extra 2 liters. I also tried shaking the fermenter with the airlock off (which I think oxidized the beer and not aerated the wort - it’s now a dark brown gross color). Final attempted fix was pitching a pack of dry us 05, which did absolutely nothing to the gravity.

Possible culprits include:

Bad tilt readings

Some silver/black grime came off the claw hammer AFTER brew day cleaning, so maybe that killed the yeast if it made it to the fermenter.

Frozen 2-liter shocked the yeast into dying and my floating tilt didn’t pick up on the temp fluctuations.

Bad yeast?

Any other ideas or feedback is welcome!
 

marc1

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Did you double check the gravity with a hydrometer?

Pitch a healthy starter of wet yeast or an appropriate amount of dry?

I would not aerate after fermentation is well underway.

If the gravity was truly stuck there, I would recommend adding glucoamylase to the fermenter to allow the yeast to take it down close to 1.000. Dry can be enjoyable, that sweet probably not.
 
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Greynolds16

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Did you clean the Clawhammer before using?
I did! But apparently not well enough? I gave it a few hour soak in pbw and tans it through the whole system for a few minutes, then I flushed it with water. Still had weird gunk in it though
 
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Greynolds16

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Did you double check the gravity with a hydrometer?

Pitch a healthy starter of wet yeast or an appropriate amount of dry?

I would not aerate after fermentation is well underway.

If the gravity was truly stuck there, I would recommend adding glucoamylase to the fermenter to allow the yeast to take it down close to 1.000. Dry can be enjoyable, that sweet probably not.
I’m going to double check the gravity when I officially dump it to make sure it’s not the tilt.

I added nearly a full pack of US 05 to it after 24 hours of being stuck, though that’s where it oxidized. My initial yeast pitch was omega Kolsch 2, which has been a little iffy in the past once before. Yeast was fresh though, straight from homebrew shop
 

RM-MN

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I also tried shaking the fermenter with the airlock off (which I think oxidized the beer and not aerated the wort - it’s now a dark brown gross color).
You stirred up all the trub and think you oxidized the beer because it turned dark brown? Give it a week for trub to settle out again and see if that helps.
Bad tilt readings
Any time you suspend a hydrometer of any kind in the fermenting beer, krausen likes to stick to it. Krausen floats which will hold your tilt up. Add to that the bubbles of CO2 that the yeast produces and you can have a very wrong reading. Tilt hydrometers are a fun way to see how quickly or slowly a fermentation is proceeding but not a definitive way to tell what the FG is. Use a real hydrometer with a sample removed from the fermenter to tell the FG.
I’m going to double check the gravity when I officially dump it to make sure it’s not the tilt.
Dump beer? Not until you have verified you really have a problem. Taste it. If it doesn't taste gross, bottle it. Beer changes after being carbonated.
 

seatazzz

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+1 to the above. There's a discussion going on in What I Did for Beer Today about tilts; some people love them, some not so much. It's a great concept, but hydrometers are not only more accurate, but dead simple. And nothing beats just tasting it to see if it's something you will like.
 
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Don't dump until you know it's bad. The Tilt is notorious for getting lofted by krausen. I just had a recent scare with my Sabro SMaSH, use a hydrometer and confirm. Give the sample jar a sniff and taste test once you confirm gravity. Lets start off with your process...What was you malt bill? Mash schedule? Confirmed OG with hydrometer/refractometer? Fermentation schedule/temps? When you are referring to Kölsch II, what do you mean "iffy"? From the sounds of it as of right now, it might be done.
 
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Greynolds16

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I FIGURED IT OUT! I ended up dumping this batch after the US05 did nothing to help - then I made an entirely different recipe and the same thing happened.

This allowed me to rule out a lot of things so I had to check the temperature readings on my new clawhammer - and it turns out I was mashing at around 170 F. I just calibrated the system and should be making beers that can actually ferment.

In an effort to save the wort of the second batch (west coast IPA using Omega star party) I added glucoamlyase. It took off fermenting so vigorously that I needed a blow off tube, so I may have a super dry IPA on the way.

In defense of the tilt, it was off by 0.001 when I compared to the hydrometer reading
 
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Greynolds16

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Another follow up: adding glucoamylase did turn it into a very dry IPA - but it became a bit thin and was all thiols. It did end up somewhat drinkable
 
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