Pinpointing source of off-flavor

[acarter5251]

I've been brewing off and on for a little while now, and as of late I have been getting the same kind of off-flavor with everything I've been brewing (a saison and a kolsch have been my latest 2 victims.). I deep cleaned all of my equipment after the saison turned for the worst, but I just started tasting it with the kolsch now too. It seems that the beers taste fine out of the fermenter and right after conditioning but after sitting in the fridge for a few more weeks, they get the off flavor.

If I had to describe the off-flavor, it's almost cherry-like and maybe a little bit on the metallic side. It's also fairly solvent-like with a burn going down.

Prior to this flavor coming up, they tasted excellent and I was very happy with them.

Any ideas as to how these off-flavors are finding their way in and developing so late in the process?

Thanks in advance!

 

[Build]

Sounds like it might be caused by oxidation or benzaldehyde. Do you keg or bottle? Is the flavor present regardless of yeast, fermentation temps, types of hops, etc?

 

[acarter5251]

I've had it happen with bottle and keg now. It has happened with multiple types of yeasts and with quite varied temperatures (saison I let rise up into the 80s. Kolsch was low 60s). The last one that didn't have that taste was an imperial stout and I'm not sure if that is just because the flavor was so strong it overpowered the off flavor

 

[Build]

What kind of water are you brewing with? Have you changed anything with your process or equipment?

 

[acarter5251]

I brew with distilled water that I have added calcium chloride and gypsum to typically. As far as any changes, I used a wort chiller I had just gotten last time, but otherwise my process is the same as it has always been. I did notice that I get an air pocket between the hook in the cane of my siphon and the tubing when I transfer from time to time, but other batches I haven't noticed the off flavor in have had that same pocket when transferring so I'm not sure if that's my issue.

 

[Build]

I don't think a single air pocket would cause much oxidation or other problem. If the chiller is sanitized I think that's fine too.

 

[acarter5251]

Looking back on it, it's been pretty hit or miss as far as the off-flavor goes. I've had a few great batches in between each of the bad batches. I think the benzaldehyde sounds about right as far as the description of the flavor goes though so at least I can rule out some sources

 

[Build]

Maybe you're picking up a rogue beta glucosidase yeast? They can cause a sour cherry flavor.

 

[acarter5251]

Would it be able to plug along very well in cold fridge temperatures though?

 

[acarter5251]

Just popped open a bottle from the same batch and same flavor as the kegged

 

[Barley_Bob]

Are you using Brun Water (or a similar service) to calculate how much of the salts you should be adding?

How long is the beer sitting in the bottle or keg before the flavor emerges?

Are you tasting this in your hydro sample?

How are you sanitizing your priming solution (where applicable)?

Ooh, what about your thermometer? Have you gauged it to see if it's reading right during fermentation?

 

[acarter5251]

I typically use the water primer on here for my additions of salts.

Usually the flavor comes up maybe a month into sitting in the bottle/keg

I don't taste it in the hydro samples and I don't taste it in the beer before the flavor emerges

I boil the priming solution for 5-10min usually. Sanitize my bottling bucket with star San before transferring beer.

Thermometer may be off by a degree or two but i don't think it would be enough to matter too much

 

[h22lude]

I get an off flavor in my batches too but it isn't what you are experiencing. I just can't put my finger on what the flavor is which is making it hard to determine what to fix so my next batch I'm fixing everything. I deep cleaned my system. I got a water report and adjusting calcium and mash using Bru'n Water. I'm going to keg half and bottle half. The only variable that isn't changing is my bucket. I may even replace it before brewing to eliminate that. At that point everything would be new except for my kegging system. If the kegged beer has the flavor but the bottles don't, then I know it is my keg. If both still have the flavor then I may hang up my brewing hat lol

Try to do something similar. Eliminate all possible variables and anything left try to test (like I'm doing with kegging and bottling). I didn't read anything about your mash ph. Do you test that?

 

[acarter5251]

I don't. Usually just throw in 1-2% acidulated malt if I'm not brewing something like a stout with lots of dark malts.

As for eliminating variables I did that this last time with bottling and kegging. So it has to be something between it coming out of the fermenter and into the bottles/keg I think. The benzaldehyde sounds about right though so I may try another batch and just try to be super careful about oxidation and see what happens

 

[h22lude]

I would think that would bring the mash ph in line but you could just check with Bru'n Water. Should be good. My tap water has a pH of 9.6 so it is high to begin with. I didn't adjust it for any beer. I'm hoping my mash pH was high and that cause the off flavor.

You could check into any plastic you have and replace it and also eliminate as much O2 as possible.

 

[acarter5251]

Yeah before this latest batch I deep cleaned and sanitized everything I had to see if it was an infection. I decided I was going to split it between bottles and keg to see if the problem was one of those. It doesn't seem to be either of those, so I guess back to troubleshooting with my next batch. Maybe I'll just do some kind of SMASH and see what happens...

 

[h22lude]

I'm brewing Yooper's Fizzy Yellow beer my next batch to figure it out. That should be light enough for any off flavor to come through.

I'm trying to eliminate anything possible. Everything will be crazy clean. Water adjustments and mash pH in line. Ferment right in the middle of the yeast range. Eliminate O2. Only thing left would be kegging or plastic parts.

 

[Ozarks Mountain Brewery]

tried this source yet?
http://howtobrew.com/book/section-4/is-my-beer-ruined/common-off-flavors

 

[acarter5251]

Yeah I have. The closest in there to what I have I'd say is the solvent flavor

 

[Ozarks Mountain Brewery]

do you flysparge or sparge with high temp water?

 

[acarter5251]

No sparging since I do BIAB

 

[h22lude]

Do you do a mash out? I mash out at 170. I do e-biab. My next batch I may remove my grains after mashing and raise the wort to a boil while draining the grains. That will basically be my mash out.

edit: I will note that a higher mash out temp alone may not extract tannins. A high mash out temp with a high mash ph would.

 

[Ozarks Mountain Brewery]

I would check your fermentation temperatures, keep it low. boil everything, don't use it unless its coated with starsan, keep your crush medium low but "not too fine", check your ph

 

[acarter5251]

I drain and raise to a boil.

My fermentation temperatures are typically at the lower end for the yeast so I don't think that's the issue. I'm just going to plug along and keep track of some of my overlooked variables (which pieces of equipment I used) and try and pinpoint as I go

 

[h22lude]

One thing you can do (not sure if would help or not), you could brew an extract batch. This will eliminate water, mash ph, mash temps, and all the other AG steps. If you still get the same taste, you know it isn't your process and you need to look at your fermentation and kegging process.

 

[Barley_Bob]

One thing you can do (not sure if would help or not), you could brew an extract batch. This will eliminate water, mash ph, mash temps, and all the other AG steps. If you still get the same taste, you know it isn't your process and you need to look at your fermentation and kegging process.

This is a pretty solid idea. Buy new yeast too if you're not doing that already.

 

[acarter5251]

Thanks! I'll give that a try as well!