Acetylaldehyde?

So I just filled my keggerator with two beers that have been aging in secondary for 6 months (cool, dark, brew room). I waited for them to carb and then eagerly pull a pint of rye cream ale and vanilla porter...

...and taste apples. In both.

I've been over everything -- long primary and secondary...used vodka in the airlocks...I only made one change when I brewed those beers...

...I used star-san.

So now I'm thinking the "star san in a spray bottle" is not adequate to kill all nasties that may produce this (frankly undrinkable) beer-flavor. Now I'm brewing again this weekend (too long in between I know!) and I think I shall resort to my iodophor standby...

Am I missing anything else that could have caused this?

- tlarham

If you use it correctly, it's not the starsan. Since you had the problem before the starsan, I doubt that's the problem. It'd help if you'd post your processes and sanitation ritual.

Acetylaldehyde isn't associated with infections...its associated with stressed yeasties not cleaning it up, since its a natural by product of fermentation. even a long primary may not clean up excessive production.

Let's talk more about your yeast pitching temps, quantities, hydration and aeration techniques as a culprit.

moosetav said:

If you use it correctly, it's not the starsan. Since you had the problem before the starsan, I doubt that's the problem. It'd help if you'd post your processes and sanitation ritual.

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+0.5, I agree that it is most likely not the sanitation (but the OP states this is the first time he had the problem and first time using star san, therefore I can understand jumping straight on star san as the cause)
What yeast did you use, and what were the og. and conditioning temp?
Maybe the yeast got tired/lathargic and couldn't be bothered cleaning up their acetylaldehyde.

Rehydrate a packet of S-05 and dump it in there. Might work.

Upon reflection it was also the first time I tried using Nottingham yeast, and a temp-controlled water bath for fermentation (68 degrees -- 2 weeks primary).

With the porter I messed up the rehydration, and after 2 days of no activity I sprinkled a dry packet on top. Fermentation picked up after that.

I just sprinkled 2 packs for the cream ale.

That seems now to be a stronger contender for a cause....

Did the Nottingham yeast happen to have an expiry date of 12/2011?

Captain_Bigelow said:

Did the Nottingham yeast happen to have an expiry date of 12/2011?

Click to expand...

Couldn't tell you unfortunately...long gone.

malkore said:

Acetylaldehyde isn't associated with infections...its associated with stressed yeasties not cleaning it up, since its a natural by product of fermentation. even a long primary may not clean up excessive production.

Let's talk more about your yeast pitching temps, quantities, hydration and aeration techniques as a culprit.

Click to expand...

I hope you gain some insight into this because I've been dealing with the same issue. As Malkore points out, it's probably something to do with fermentation (yeast, temp, etc). I've been using StarSan for many many years without issue.

I lost 5 batches in row (after successfully brewing over 100 batches). I've used at least 3 different strains of yeast that I stepped up. I tried using a yeast nutrient. I tried adding more 02. Replaced all my hoses (thinking it might be an infection). The list goes on, but batch after batch I got the same results. So there is a constant - I started doing something differently that is causing this. In fact, I took time off from brewing b/c I just got too damn frustrated.

If you look up Acetylaldehyde in most brewing books it states that it will clear up w/ a longer secondary. But in my case that has never happened. I now believe it's something causing the yeast to stop mid-fermentation or at least slow down; something is stressing the yeast out and it's never finishing properly. I have asked 3 highly respected professional brewers and/or brewing scientits and I have yet to get a good understanding of what may be causing this (beyond the text book explanation).

Now that I've been down the rabbit hole several times, I'm leaning toward fermentation temperatures. Again, no evidence yet. But the only thing I changed was adding a new fermentation fridge with a dual stage controller to heat and cool. I have a heating pad inside and usually leave the differencial to 2 degrees. The other thing I changed was I now take the temp of the beer using a probe. Where as before I just kept the temp of the fridge at a constant. So maybe somethings causing the temperature of the beer to fluctuate too much. No idea. As I write this, now I'm thinking maybe it's something with my wort - did I change something that is causing me to produce sub-standard wort? No idea.

On my next batch, I'm planning on going back to basics. I'm going to use a carboy, pitch from a vial, manually shake it, and put it in the temp controlled fridge set to 68F. If that batch turns out, then I'm going to slowly change things until it happens again. Either that or I'm going to take my 9mm and use my brewing system as target practice!

Only reason I jumped all over this, is much of my current beer stock is 'cidery'. (well that and the fact I've drank star-san plenty of times and there's just no way you should taste it in your beer)

Not terribly cidery, but enough that people in my brew club asked about my yeast pitching procedures, and upon reflection I do abuse the little guys lately.

Plus it was all older yeast that I thought I'd just get used up, including some Notty and Windsor. I'm now putting a lot more stock into FRESH yeast, and starters for ALL liquid pitchings...while maintaining good fermentation temps and aeration at pitching.

In fact I'm taking a step back from AG on my next brew just so I can put the focus on the yeast and not the mash/sparge/boil phase.

All I need is a second temp controller and I'll have a real fermentation chamber available too.

(continues rambling off into the next thread...

You may want to familiarize yourself with the recent controversy of notty yeast not starting quickly or fermenting as is usual experience and it's subsequent recall.

I do not think your issue is with the star san if you are mixing it correctly and using it correctly, and frankly it ain't hard to do either one. To be sure, you should verify that you are mixing it correctly and allowing enough time exposure with it in your vessels and gear, but as already said, it is a fermentation issue.

Are you properly aerating your wort or using oxygen before pitching the yeast? Are you pitching and fermenting at the correct temps? Was the yeast even within viable date?

There is much debate about the latest notty yeast controversy-some swear there isn't an issue and some have absolutely no doubt that there is something going on with a certain batch lot. I'd be checking your yeast packet's lot numbers and dates if you have any more of it, and read the 5 or so threads on the subject.