Another BIAB tannin extraction thread

I recently found myself with a very rare day off and decided that I had to brew a batch for the pipeline's sake. To keep things simple I decided to BIAB. I knew things wouldn't be very predictable as this was my first true BIAB and I bought the grain from a local brewery pre-crushed rather than using the usual sources and crushing myself.

The recipe was pretty a simple IPA, 2-row base, 8% wheat, 8% Crystal which was supposedly C45, but looked more like 120 or even 150. I ended up getting pretty low efficiency, and got a 1.053 wort, 7pts lower than my target 1.060. I started the mash out at ~153* which fell to something like 142 over 60 minutes, so I fired it up to 158 for 15 minutes before stepping up to 168 for mash-out. I stirred quite a bit during each of the step ups, but I am still concerned that there may have been some tannin extraction from higher temps at the bottom of the kettle.

After primary fermentation was complete (~5 days) I took a sample. It was crushingly bitter. Now, I've only experienced tannin extraction once on any real scale, and that was the result of over-sparging the small beer of a partigyle. This bitterness could be described as astringent, but it struck me as different than the astringency in the small beer which was pretty much undrinkable. I described this in my notes as a somewhat dry bitterness in the finish, similar to the bite of unsweetened grapefuit juice. Beersmith predicted the IBUs at 60 (Tinseth). I took another sample the other day at 3 weeks in primary and the harsh bitterness/astringency has mellowed somewhat, but is still very noticeable. So I'm wondering if the low starting gravity combined with the hop bill has just created a monstrously bitter beer, or have I extracted the dreaded tannins and ruined the batch.

I don't have the hop bill in front of me, but it is something like this:
Columbus, 60 minutes ~45 IBU
Cascade at 20 and 10 minutes to fill out the 60 IBU
Chinook at flameout
All whole hops

It's probably hop bitterness. I've found that if I bitter with columbus that the beer comes out with a harsher bitterness than if I bitter with a low alpha variety like cascade. Same IBU's, but different none the less.

I tend to agree. This is the first time I have used Columbus to bitter an average gravity beer, I mostly use it in huge DIPAs. This beer was supposed to be 100% Chinook, but at the last minute I realized that I only had a couple ounces left and had to improvise.

And correct me if I'm wrong, but if it were tannins, the astringency wouldn't mellow over time (or at least not a short period of time), right?

Ive never experienced astringency (knowingly anyway). So I don't know. However, astringency should only be a problem if the mash pH gets too high. Ie, if you sparge too much. I don't think that "higher temps at the bottom of the kettle" would result in significant tannin extraction. If that was the case, I would think that decoction mashing would leave everyone with puckered faces.

JuanKenobi said:

I tend to agree. This is the first time I have used Columbus to bitter an average gravity beer, I mostly use it in huge DIPAs. This beer was supposed to be 100% Chinook, but at the last minute I realized that I only had a couple ounces left and had to improvise.

And correct me if I'm wrong, but if it were tannins, the astringency wouldn't mellow over time (or at least not a short period of time), right?

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Ya know, this explains a lot. I've been noticing some astringent notes in my beers that mellow over time. I bought a pound of Columbus a year ago and have been bittering with that quite a bit. I've got an IPA planned I bought some Horizon for, it'll be interesting to see what happens.

I prefer to use columbus for aroma/finishing and especially dry hopping.

It's still too early to tell. During fermentation, a lot of bitterness is lost. It may be done fermenting, but every beer I've tasted at 5 days was still a lot more bitter than the final product. It will probably mellow.

There are a lot of people with direct fire mash tuns who do exactly as you do with no issues. Also consider people who have been doing decoctions for centuries without tannin issues. If boiling part of the mash doesn't ruin the beer, I doubt heating up the mashtun would.

BTW, I maintain and raise my mash temp with a heat stick. It's got to be the most uneven way of doing it causing very high temp differences in the mash. I don't have an issue with tannins.

BBL_Brewer said:

Ive never experienced astringency (knowingly anyway). So I don't know. However, astringency should only be a problem if the mash pH gets too high. Ie, if you sparge too much. I don't think that "higher temps at the bottom of the kettle" would result in significant tannin extraction. If that was the case, I would think that decoction mashing would leave everyone with puckered faces.

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This makes sense, but isn't the reason that you don't want your mash temp going over 170 that the tannins and other undesirables from the grain husks become soluble at higher temps?

seabass07 said:

It's still too early to tell. During fermentation, a lot of bitterness is lost. It may be done fermenting, but every beer I've tasted at 5 days was still a lot more bitter than the final product. It will probably mellow.

There are a lot of people with direct fire mash tuns who do exactly as you do with no issues. Also consider people who have been doing decoctions for centuries without tannin issues. If boiling part of the mash doesn't ruin the beer, I doubt heating up the mashtun would.

BTW, I maintain and raise my mash temp with a heat stick. It's got to be the most uneven way of doing it causing very high temp differences in the mash. I don't have an issue with tannins.

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I agree that 5 days is too early to tell anything, but it is always good to know how your brews evolve. I also tasted it at 3 weeks primary, which is still very early, I know. It's just that this level (or flavor) of bitterness is something that I haven't experienced before and I brew DIPAs that calculate to 150 - 200 IBUs.

I've never done a true decoction before, but doesn't it involve running off some of the mash and boiling that? So the grain wouldn't be involved with the boiling portion in any significant way, would it?

Thanks for the input everyone. I suspected that it was just hop bitterness, but I figured I'd throw it out there so that I could get some feedback. It actually didn't occur to me that it could be anything but the hops until I was drinking the second sample.

On another note, I was also trying to decide if I wanted to try to do something to fix this batch or just go with it as-is. I actually think this could turn out to be a pretty good beer as long as you don't mind a crushingly bitter beer. But, then again, it's such a weird brew already due to the wacky crystal malt the local brewery sold me. So I was thinking of making like a half gallon of unhopped high gravity wort from DME and some D2 candi syrup that I have left over from a dubbel and toss that in with a little fresh yeast and call it an American Dark Ale or some such thing.

Don't quote me on this but I'm pretty sure what you're pulling off and heating in decoction mashing is a thick grist with the grains, like oatmeal: not too wet or too dry.

SenorPepe said:

Don't quote me on this but I'm pretty sure what you're pulling off and heating in decoction mashing is a thick grist with the grains, like oatmeal: not too wet or too dry.

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That's correct. You pull off a thick part of the mash including grain and boil it.