Pepper off flavor in stout

[zam216]

So I entered 3 beers in a local competition this weekend, one being a founders breakfast stout clone recipe. One thing the judges and myself noticed in the beer was a green pepper, as they described, off flavor. I got the same thing with this beer after about a week in the keg. I have done some research on why this would happen and the only thing I have found was the coffee. This has recently happened to me on another coffee stout I did so it makes sense. For this past recipe I used the 2 different types of coffee the recipe calls for one in the boil and one cold brewed in the secondary. I used coffee grounds. for the boil I threw them right in at knockout and cooled quickly. The cold brew I put the grounds into a mason jar with room temp water and let it sit for 24 hours and strained through a sanitized coffee filters and pitched right into the carboy. Prior to pitching it tasted fine just like coffee and the wort coming out of the boil was fine.

The recipe follows:

13lb 2 row
1lb 6oz flaked oats
1lb chocolate malt
12oz roasted barley
9oz black patent (I think I subbed this out for another black malt)
7oz crystal 120

.5oz nugget 60 mins
.5oz willamette 30 mins

2.5oz dark bittersweet bakers chocolate 15 mins boil
1.5oz cocoa nibs 15 mins boil
2oz ground sumatran coffee knockout
2oz ground kona coffee cold brewed secondary

WLP001


I use sanitary practices and clean and sanitize everything and keep it wet with star san prior to using so I doubt it was an infection. The judges said the base stout was very well done but the coffee and pepper over powered. I would love to fix this problem to work on this beer and others like it for the future.

 

[poptarts]

I have read a lot that coffee grounds give beer a green pepper flavor, but it appears you didn't put grounds into the beer.

 

[zam216]

I have read a lot that coffee grounds give beer a green pepper flavor, but it appears you didn't put grounds into the beer.

No I did use grounds in both the boil and secondary. Do you think whole beans would not do this?

 

[Doctor_M]

It's definitely the coffee. I'm not sure why sometimes it throws green pepper and sometimes it doesn't though.

 

[enokidaki]

Funny this should come up today as yesterday I was sampling country boy's 8% coffee stout and spent the whole time trying to place this hint of spice I called a mild jalapeno taste. So I just imagined it was on purpose and I rather enjoyed it!

 

[LKABrewer]

You will extract different flavors from the coffee beans at different temperatures and pH levels. The best way to avoid the green pepper/green bean flavor is to cold-steep the coffee in sanitary water, then add to secondary. This will make sure you get the coffee flavor at low temperature and normal pH.

 

[zam216]

You will extract different flavors from the coffee beans at different temperatures and pH levels. The best way to avoid the green pepper/green bean flavor is to cold-steep the coffee in sanitary water, then add to secondary. This will make sure you get the coffee flavor at low temperature and normal pH.

That was what I was thinking of doing for my next one. So do you know what the pH level should be to not extract off flavors? Is this something I can treat like I would mash or sparge water? Also, for recipes like the breakfast stout that call for a boil addition and a secondary addition would it make sense to add cold brew to the boil or maybe pitch it in during the cooling process or whirlpool so the temps are lower?

 

[MindenMan]

My last coffee stout I added cold pressed coffee done in the fridge to my bottling bucket. Cold pressed coffee has less of a tendency to release the oils we sometimes perceive as bitter or "off". It was overpowering in the beginning with the coffee flavor running rampant, but after 9 or so months it was really nice. To me raw cocoa nibs taste like cheap chocolate hard candy, but after they are roasted and made into an extract they are completely different. Once again, a flavor for the bottling bucket that will be very predictable. The Maltose Falcons IIRC have a chocolate stout/porter recipe that has won a few awards; I believe they add cocoa powder just before flame out. Cocoa powder does give a nice cocoa note (think hot cocoa mix) but it doesn't taste like chocolate per se. Roasted cocoa nibs that have been crushed into vodka will give a milk chocolate flavor, but in my experience the nibs need to steep for weeks not days.