I made a chocolate stout a while back that's kind of astrigent. I'm not sure I would call it sour, but it makes you pucker a bit. It had 8 oz of Trader Joe's Tumaco cocoa powder added in primary, no secondary. I've read that alkalized or Dutch processed cocoa powder reduces the acidity and astrigency, so I think it was the cocoa powder that caused it. The base recipe was the partial mash oatmeal stout from Brewing Classic Styles. No lactose involved because I have lactose intolerant and allergic friends & family.

Has anyone else had a similar experience? Do you think non-alkalized powder could be the culprit? Would that make Dutch processed better for adding to beer?

  • The lactose in the recipe may have balanced out the astringency.
    – baka
    Commented Sep 12, 2012 at 13:21
  • There is no lactose in the recipe, that's why I picked it. Oatmeal stout - not sweet or milk stout.
    – paul
    Commented Sep 12, 2012 at 17:11
  • Oh, I misunderstood your comment about lactose not being involved.
    – baka
    Commented Sep 12, 2012 at 18:09
  • Maybe it just needs to age a bit to mellow the flavour? Commented Sep 13, 2012 at 15:44
  • 1
    More astringent over time sounds like an infection to me. I have an Oatmeal Porter that has gotten more astringent after starting out pretty smooth, and its much more carbinated now, indicating further microbial activity.
    – GHP
    Commented Sep 14, 2012 at 17:00

2 Answers 2


My brewing buddy and I brew a chocolate oatmeal stout around this time each year. I add in a whole container of cocoa powder and I have never had any issues with astringency. I have tried both natural pressed cocoa and Dutch processed cocoa and haven't noticed a big effect on astringency. I typically add it to the boil, not sure if that may be the reason why you are having issues.

There are a couple of possibilities here:

  1. The cocoa had some wild yeast which added some funk to the brewing process, which is actually very likely considering that cocoa beans must be fermented in order to be processed.

Solution: Add the cocoa powder to the boil, which would kill any yeast in the cocoa.

  1. If you did all grain you may have over sparged which leads to more tannins in the beer which would definitely lead to a lot more astringency.

Solution: Don't sparge with as much water or with as hot of water. Watch closely the color of the sparged liquid going into the brew pot. You could use either the iodophor test or get a refractometer if you want to be really sure of when to stop spargin.

  • There's no funk and I'm pretty sure it's not an infection, although I did not boil the chocolate - just added it directly to the primary as recommended in the recipe for Jamil's chocolate hazelnut porter. Base recipe was a partial mash extract brew (McQuaker's oatmeal stout). About 5 lbs of grain + 5.4 lbs LME at 155°F, so there was no sparge and pretty low temps, so I think tannin extraction was unlikely, but I suppose it's possible.
    – paul
    Commented Sep 14, 2012 at 19:37
  • I agree your partial mash method makes it unlikely that you would get an excess of tannins. But I wouldn't discount the possiblity of a wild yeast strain from the cocoa taking off and producing this off flavor. Apparently cocoa is roasted before being pulverized to powder form, and this could kill all the yeast that were in there originally, but not any that came after processing. From reading some more apparently natural cocoa powder is acidic. So depending on your water and such it could be a reaction that happened in primary. My only suggestion is to try boiling it next time. Commented Sep 14, 2012 at 21:14
  • I am pretty sure Jamil boils the powder. I made the same recipe a few years back and dropped the cocoa in with 5 minutes left in the boil.
    – brewchez
    Commented Sep 15, 2012 at 0:48
  • With mine I add the cocoa powder 10 minutes to the end of the boil. But I bet it doesn't make that big a difference. Commented Sep 19, 2012 at 21:05

I have not used this cocoa powder, but most cocoa powder that's not sweetened is fairly harsh, and needs a good sweetness backbone to push against. The astringency which can come from both acidic and alkali compounds could be also from the other grains in the grist as well as the chocolate.

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