Stout has acetaminophen (tylenol) aftertaste

[brag]

TL;DR : My beer has an acetaminophen (tylenol) aftertaste, what could this be ?

I brewed an espresso oatmeal Stout 4 months ago. It had a hard time carbonating and has an acrid/bitter (burnt? too much dark malt?) aftertaste. It mellowed a bit with time. To me, this aftertaste now resembles acetaminophen (without the coating, just the white stuff, which is pretty bitter).

Recipe : https://www.brewtoad.com/recipes/espresso-oatmeal-stout-3

 

[RM-MN]

I'd suggest you let this beer sit for another 2 months as the flavor will still be changing. If you need something to drink sooner, do a lighter colored beer because they will be ready to drink much faster than the dark beers.

 

[iamwhatiseem]

What do you use to clean your equipment with?

 

[helibrewer]

What was the full recipe?

 

[ong]

The only thing that seems a bit odd in the recipe is the mash temp -- did you mash at 63 Celsius the whole time (145 Fahrenheit)? That's pretty low for a stout, to my mind.

I don't agree that a stout shouldn't be ready to drink after 4 months! (Especially at 1.051 OG!) That ought to be plenty unless you're talking a huge (RIS) beer.

 

[iamwhatiseem]

I don't agree that a stout shouldn't be ready to drink after 4 months! (Especially at 1.051 OG!) That ought to be plenty unless you're talking a huge (RIS) beer.

I was thinking the same thing. I have a couple stouts that are close to that OG and they are very drinkable as little as 3 weeks after 1 month in primary.
One question...how did you put in the coffee? If you put the coffee in while the wort was boiling still that would produce an astringent/tea bag bitter taste.

On a side note, the lowest coffee stout I make has an OG of 1.064. In my opinion, your grain content is not high enough for nearlly a pound of coffee.
My recipe has 12.25 lbs of grains! If my math is right your recipe isn't even 8 lbs. Seems very odd to me.

 

[ong]

On a side note, the lowest coffee stout I make has an OG of 1.064. In my opinion, your grain content is not high enough for nearlly a pound of coffee.

My recipe has 12.25 lbs of grains! If my math is right your recipe isn't even 8 lbs. Seems very odd to me.

I read the coffee addition as 400ml of brewed coffee, rather than beans, which doesn't seem excessive to me. I would add this in secondary, too.

 

[ong]

Oh, it says right in the recipe that the espresso was added in secondary. I believe Guinness is brewed to around 1.052 OG, so it's not an unreasonable gravity for a stout.

 

[ong]

My recipe has 12.25 lbs of grains! If my math is right your recipe isn't even 8 lbs. Seems very odd to me.

Note the batch size of 14.5l -- not a 5 gallon batch.

 

[brag]

I use pink bleach to wash my fermenters, then rinse 3 times. I sanitize everything (including fermenters after rinse) with oxy-san (a no rinse sanitizer).

I mashed low because I wanted a dry-stout-ish beer. That is also why I did not put any caramel malt.

@ong is right, the coffee was 400ml (~ 2 cups) of brewed espresso, added at bottling.

Yes it was a ~4 gal batch.

I had a St-Ambroise Oatmeal Stout (http://www.beeradvocate.com/beer/profile/194/2704/) this afternoon, and picked-up a little bit of the same aftertaste. Maybe this is normal dark grain bitterness... My next batch will definitely be mashed higher, maybe a bit more hops (with some late additions), and some caramel malt; this should produce something better balanced...

Also note that the beer may be a bit under-carbonated, as I was scared at bottling that it would go down 1 more point, so I aimed maybe a bit less than 2 vol CO2... Also, is was slow to carbonate, so it may just not be there yet.