Acetaldehyde....

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TrustyOlJohnson

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Well, after having successfully fermented about 12 ales using a schedule of 7 days each at 62/65/68 degrees, I fermented 2 batches at the same time, one a Northern Brewer Honey Brown ale with US-05 and a Thunderstruck Pumpkin Ale with Nottingham. This time I tightened the schedule to 5 days each at 62/65/68. At bottling, both seemed fine. I used honey for the Honey Brown and corn sugar for the pumpkin ale. Now after 2 weeks + in the bbottles, carbonation is good,
 
johnpcook1 said:
Well, after having successfully fermented about 12 ales using a schedule of 7 days each at 62/65/68 degrees, I fermented 2 batches at the same time, one a Northern Brewer Honey Brown ale with US-05 and a Thunderstruck Pumpkin Ale with Nottingham. This time I tightened the schedule to 5 days each at 62/65/68. At bottling, both seemed fine. I used honey for the Honey Brown and corn sugar for the pumpkin ale. Now after 2 weeks + in the bbottles, carbonation is good,
But, I have a slight not of Acetaldehyde. It is hard to taste the spices or honey. My question, what if I shake all the bottles and keep them at room temp? Is it possible the acetaldehyde will be cleaned up? Has anyone had success with this?
 
John, two weeks is pretty young to me, if they're green now wait a couple weeks, it will clean up at room temp. I don't think shaking the bottles is necessary or advisable.
 
Shortening the fermentation time will likely expose more off flavors since the yeast are not getting through their entire cycle. Not sure how easy the cleanup will be in the bottle. I don't think you have enough active yeast to tackle the bottles volume of by-products.

Are you just trying to determine your minimum cycle to produce ale?
 
My thinking was, that ive had success with three week fermentations, but had heard so many success stories of two week fermentations for both homebrewers and microbreweries. So, basically it was an experiment. The odd part is, at bottling, I didnt detect any off flavors. Having brewed my first four batches of beer with intense acetaldehyde due to fermentations at too high of temps, ive got a nose for this stuff (and a fermentation chamber :) ) What wud be the concern associated with shaking the bottles to rouse the yeast and waiting two weeks to clarify?
 
My thinking was, that ive had success with three week fermentations, but had heard so many success stories of two week fermentations for both homebrewers and microbreweries. So, basically it was an experiment. The odd part is, at bottling, I didnt detect any off flavors. Having brewed my first four batches of beer with intense acetaldehyde due to fermentations at too high of temps, ive got a nose for this stuff (and a fermentation chamber :) ) What wud be the concern associated with shaking the bottles to rouse the yeast and waiting two weeks to clarify?

No concern. My only thoughts were that with bottling the yeast population is very small and the clean-up might be insufficient...it is certainly worth a try.
 
So, basically it was an experiment. The odd part is, at bottling, I didnt detect any off flavors.

This seems odd to me - from where would the acetaldehyde magically appear..?
Priming-sugar consumption? At what temperature did you bottle-carbonate?
 
Its very weird. Bottled at room temp, 70 ish degrees. Both batches the same day. And the day I bottled the pumpkin ale, it had a great spice profile! My son and I drank glasses of it at room temp. Now, the spices cant be detected 3 weeks later
 
johnpcook1 said:
My thinking was, that ive had success with three week fermentations, but had heard so many success stories of two week fermentations for both homebrewers and microbreweries. So, basically it was an experiment. The odd part is, at bottling, I didnt detect any off flavors. Having brewed my first four batches of beer with intense acetaldehyde due to fermentations at too high of temps, ive got a nose for this stuff (and a fermentation chamber :) ) What wud be the concern associated with shaking the bottles to rouse the yeast and waiting two weeks to clarify?

You can have a <two week turn around on some styles but breweries who are turning beer around less than two weeks are using a large pitch of active yeast, great fermentation control and are filtering the beer to speed things up. Time is money for them and the longer a beer sits in the tank, the less money they make.
 
Primary longer.....MUCH longer.

15 day primaries should be plenty of time for a normal gravity ale as long as your brewing and fermentation processes are good.

No concern. My only thoughts were that with bottling the yeast population is very small and the clean-up might be insufficient...it is certainly worth a try.

The yeast population in solution in the bottle is the same as what is in solution in the primary at the time of bottling. So with the exception of the yeast cake on the bottom (which is mostly inactive) you should get the same amount of activity.

It is weird that you didn't taste it before bottling and now you do. The small amount of priming sugar wouldn't be enough to produce any noticeable off flavors. I would say just let it sit for a couple more weeks and see if it cleans its self up.

Another thought, I've heard that US-05 can produce some peachy esters when fermented in the low 60s. Could that be what you're tasting? Have you ever used US-05 at that ferment temp before?
 
My apologies, both batches also conditioned at 70 ish. I checked the brew records for both batches and given the temps outside were beginning to drop, I had to set up the heater in my ferm chamber to bring the temps up at each step. I actually was hitting lower than target numbers for ferm. I do know that, from experience, I have to have a clean palate (i.e. no previous beer drinking) to detect slight levels of acetaldehyde. And I might have had one or two on bottling day :) I guess Im jus gonna shake all the bottles to rouse the yeast and let em sit for two weeks to clarify and check em again. And drink em. And go back to a 3 week sched.
 
A couple of quick thoughts:

Is it in both batches or just the pumpkin? I ask because at low levels, AA is often described as "green apples" but at higher concentrations it smells like "fresh/raw pumpkin".

AA can either not get reduced after the primary fermentation and this could be due to too few yeast cells present or temps too low. If this is the case, more time will help, albeit, slowly. Or, with unhealthy yeast, too much yeast (not enough nutrients to go around), the yeast die and lyse, the AA leaches out of the cells and goes up... for this, there is no cure and it will likely only get worse.
 
Primary longer.....MUCH longer.

Longer than 15 days? That seems excruciatingly long already to me!

Nottingham especially should ferment quickly, and give a super clear beer in about 7 days, so going longer in the primary shouldn't matter.

S05 does take longer to flocculate out, but it should have easily been finished by day 15. I do notice that I get "peachy" esters when I use s05 below 66 degrees, though, so maybe 62/65 is a bit cool for that yeast strain. I'd probably do more like 66/70.
 
Well, I delivered a case of the Honey Brown Ale to the very special girl that I made the batch for. I brought a few other bottles that were chilled, cause I shook up all the bottles in the case. She tasted it and is tasting the same thing I am. I strongly believe its acetaldehyde (green apple), she describes it as a bite, a twang, at the end of taking a sip. We tried 2 pumpkin Ale, and the spices are pretty strong. Tastes like pumpkin pie. I know when bottling the pumpkin ale, I had to frequently stir the bottling bucket to float the spices. I had a pumpkin pie ale earlier today, no spices with acetaldehyde flavor. My plan is to shake (rouse the yeast) of all the bottles of both batches and let them sit at room temp til I drink em. See what happens.
 
Well, my bottles had conditioned for 2 weeks and the acetaldehyde became present. So, I took the bottles and shook them all and left them at room temp. Now 4 weeks later, a total of 6 weeks in the bottle, the acetaldehyde is gone. Jus needed time to clean up the honey that i used to prime the bottles I guess.
 
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