[hogg44]

The last two darker beers I've made (a doppelbock and a scottish export) have had what I can best describe as burnt muffin or cookie flavor. Not like black burnt or ashy. More like the flavor you get from baked goods that were baked too long and are really crunchy. (Flavor description is not my forte; I'm doing my best.)

The recipes were from Brewing Classic Styles.

Doppelbock:
14# Munich
4# Pilsner
2# CaraMunich
Mash at 155

Scottish Export:
9.5# Maris Otter
1# C40
.5# Munich
.5# Honey Malt
.25# C120
3 oz Pale Chocolate
Mash at 158

I used Bru'n Water and adjusted RO water to target a pH of 5.35. I didn't actually take any pH readings.

EDIT: Mash in a bag, dunk sparge, squeeze bag, boil 45 minutes.

I thought about maybe scorching from the boil, but I made an IPA between these batches that didn't have that flavor.

Any ideas? Thanks in advance.

[802Chris]

Do you mind posting water profile and additions? Nothing looks off for those recipes. What is your efficiency roughly?

[stpug]

My personal experience with a flavor/characteristic that is somewhat similar to what you describe would be coupled with a light bit of bitterness as well - and not the kind of bitterness you get from hops.  More of a bitterness you'd get from overcooked baked goods or even the kind of bitterness you'd get from burnt sugar (just to a much lesser extent).  So far in my brewing experience the closest thing I've been able to pin it to is some kind of oxidized flavor in the beer.  In my own recipes, I would contribute it to oxidized cara malt (or malt in general) characteristics, but I have no definitive proof of this.  I've taken steps at reducing (mostly, eliminating) this character in my beers through various steps outlined in the present low oxygen brewing methods, and have been fairly successful at it.  I usually still experience these characteristics but now I'm not seeing them crop up until a keg is mostly gone which could be the result of oxygen levels going above threshold the longer the keg sits and the more co2 gas that's pushed into the keg (which contains some oxygen in addition to the co2).  Again, I'm just trying to relate what I've experienced with what you're describing, and how I've gone about tackling the issues on my end.

Then again, I may be totally wrong and barking up the wrong tree.  I'm just trying to relate my own experiences with yours.

[hogg44]

So far in my brewing experience the closest thing I've been able to pin it to is some kind of oxidized flavor in the beer.  In my own recipes, I would contribute it to oxidized cara malt (or malt in general) characteristics

After thinking about it more, my best guesses were mash pH, oxidation, or stale malts. I always read about oxidation tasting like cardboard, but I'm wondering if my perception of it is just a little different and I get this overcooked baked good flavor.

I'm going to try to really cut down on the post-fermentation aeration and see if that doesn't help.

Thanks for the reply.

[The Beerery]

So far in my brewing experience the closest thing I've been able to pin it to is some kind of oxidized flavor in the beer.  In my own recipes, I would contribute it to oxidized cara malt (or malt in general) characteristics

After thinking about it more, my best guesses were mash pH, oxidation, or stale malts. I always read about oxidation tasting like cardboard, but I'm wondering if my perception of it is just a little different and I get this overcooked baked good flavor.

I'm going to try to really cut down on the post-fermentation aeration and see if that doesn't help.

Thanks for the reply.

I was waiting so I wasn't the first guy! 

Let me get you this Hogg.

“The deleterious effects of oxygen uptake at any point in the brewing cycle is well documented. The only exception to this is the oxygen introduced at the start of the fermentation. It is true that there is a considerable variation among beer drinkers both with respect to their ability to detect oxidized flavors, and with respect totheir acceptance of these notes. Yet the track record is clear in both amateur and commercial brewing: Consistently successful brewers are invariably the ones who operate low oxygen systems. For most of the twentieth century, attention was focused on oxidation occurring after the end of the fermentation-so-called cold side aeration (CSA). Concerns about CSA are well founded since there are a number of relevant mechanisms, all of which are destructive to beer flavor.”

CSA is all over in any brewing texts and a simple google search will yield countless results. However George lays it out well here:

“Methods for such optimization are covered in, for example, in the references by Bamforth (1999) and Fix (1998). Following C. D. Dalgliesch (1977), it is useful to characterize staling in terms of three basic stages:

• Stage A is the period of stable, “brewery-fresh” flavor.

• Stage B is a transition period in which a multitude of new flavor sensations can be detected.

• Stage C products are the classic flavor tones involved in beer staling.”

He goes on to list an overview of the stages, the highlights of them being:

“Stage A beer is pristine in flavor. During stage B, Dalgliesch described a decline in hop aroma, a decline in hop bitterness,an increase in “ribes aroma” (or sometimes “catty” flavor), and an increase in sweet, toffee-like, or caramel tones. The terms ribes (or currant) and catty are widely used in the United Kingdom and Scandinavia to recall overripe or spoiled fruit or vegetables. Some tasters cite a “black currant” tone (Hardwick, 1978). In truth, these terms describe a wide spectrum of negative flavors developed when beer is in stage B. Toffee or caramel flavors can come from many sources, but those associated with staling will invariably have unattractive cloying notes. These effects are enhanced by residual diacetyl and also by excess heat treatment of wort. Finally, stage C products range from papery or leathery to sherry- or vinegar-like notes.”

This is from George Fix's book Principles of Brewing Science: A Study of Serious Brewing Issues, Edition 2

Only the LAST stage of oxidation is where cardboard comes in. Simply a loss or addition of a flavor (the flavors you are describing) are also oxidation.

Cheers and good luck!

[The Beerery]

For good measure I will add this:

https://www.morebeer.com/articles/oxidation_in_beer

[hogg44]

For good measure I will add this:

https://www.morebeer.com/articles/oxidation_in_beer

Thank you.

Any suggestions or other resources you could point me to to reduce CSA?

I bottle and I always feel like bottling day is where I'm introducing the most oxygen (transferring to bottling vessel, stirring in priming solution, starting the siphon, filling the first 1/2 inch or so of each bottle, etc.).

I don't know much about low-oxygen brewing, but my perception is that to reduce CSA, I must also increase PITA. But I'd love to find out otherwise.

[The Beerery]

For good measure I will add this:

https://www.morebeer.com/articles/oxidation_in_beer

Thank you.

Any suggestions or other resources you could point me to to reduce CSA?

I bottle and I always feel like bottling day is where I'm introducing the most oxygen (transferring to bottling vessel, stirring in priming solution, starting the siphon, filling the first 1/2 inch or so of each bottle, etc.).

I don't know much about low-oxygen brewing, but my perception is that to reduce CSA, I must also increase PITA. But I'd love to find out otherwise.

Well, being that you bottle you will have yeast to eat up that oxygen which is a great thing. If you want to get crazy add the sugar to the bottling bucket and put a lid/airlock on it and wait until you have some activity to bottle. That means the yeast have woken up, and will eat o2 for you. However I don't think your problem is actually fully CSA related. The darker beers especially full of melanoidian (munich and the like) cause basically cause the flavors your are describing in the mash because of oxidation. If you are felling frisky google "auto-oxidation of melanoidins".

Cheers and good luck

[Lazy Ant Brewing]

I do BIAB, bottle, and brew in the brown-ale-to-stout spectrum and have never experienced the off-flavors described above.

Maybe my taste isn't that sensitive.  I haven't entered any brews  into competition, but have sometimes  gotten some unsolicited good comments from guys at the local brew club meeting.