[nateo]

I've been digging through the "Search" function for a few hours now, trying to get info, but I'm at an impasse.

I've gotten a husky/raw grain/ astringent? flavor on a few beers I've done recently. The obvious culprit is tannin extraction, and the most common cause of tannin extraction is sparging too hot and at too high of a pH. I've read that tannins could also be from break material in the fermenter. But I've also read that break material and trub don't affect the beer.

Here's my process: I use the Deathbrewer BIAB method, squeeze the bag, sometimes use decoctions, batch sparge, don't filter the wort going into the kettle, or into the fermenter. Sparge @ 165* and I acidify the sparge water with 88% lactic acid to make sure it's under 5.8 before sparging. Mash pH between 5.2-5.5.

I've made a lot of beer (20+ batches) with the above method without grainy flavor. I'm trying to pin down when exactly the flavor started, and I think it was about the time I bought my last bag of malt. I've made about 6 batches with malt that was milled by a maltster, instead of my 2-roller mill. The crush is finer than I get on my mill, and extract efficiency is better. I also used to use a metal colander to strain out hop particles going into the fermenter, but in the last 6 batches haven't bothered.

Going over my brewing log, the only differences between the 3 batches with the grainy flavor and the 3 batches without has been the OG, with the lower OG batches not showing the graininess, and the high OG batches showing it.

I notice a bit more fine grain going into the boiler than before, and I wonder if filtering before the boil might help. Also, I wonder if straining the hops out pre-ferment might help, maybe by catching some of the break material in the process.

Any ideas?

[Hokerer]

Not sure what you mean by fine grains going into the boiler, but if you mean that actual bits of the grain, husks, and such are getting into the kettle, that could definitely be your problem.  Break material and hops getting into the kettle won't cause it.

[davisdandrew]

It sounds like this might be a classic case of having too much crud in the fermenter. if you are not removing anything from the wort (hops, break material) you could be picking up a lot of flavor from that which could be percieved as husky/grainy/astringent. as for this flavor increasing with the gravity, break material and usually hops increase with gravity and this could be pushing the flavor contribution past threshold and giving you flavors you didnt get in lower gravity beers.
 you should really try to remove some of that material even if it is not the source of the husky flavor problem, there are countless reasons to do so
good luck!

[nateo]

"Not sure what you mean by fine grains going into the boiler, but if you mean that actual bits of the grain, husks, and such are getting into the kettle, that could definitely be your problem."

I can see little bits of flour from the mash going into the fermenter. Doing the BIAB thing, I can't really vorlauf. Any ideas for filtration before boil? I thought about cheesecloth, but don't know if that'll catch the flour. A coffee filter would, but it would take forever to run through.

" if you are not removing anything from the wort (hops, break material) you could be picking up a lot of flavor from that which could be percieved as husky/grainy/astringent. as for this flavor increasing with the gravity, break material and usually hops increase with gravity and this could be pushing the flavor contribution past threshold and giving you flavors you didnt get in lower gravity beers."

That's what I was suspecting, that the increase in grain/hops pushed it to a level where I noticed it. Aside from whirlpooling and straining going into the fermenter, any other ideas for filtering?

[richardt]

Use a second extremely fine nylon mesh bag that fits your boil kettle and/or fermentation bucket--pour your wort into the kettle or bucket and lift out the bag when the transfer is done--it should help strain out the fine bits.

[dmtaylor]

A few thoughts...

Make sure you don't squeeze your grain bag too hard.  You could be getting unconverted starches as well as tannins.  Either one could screw up the taste of your beer.  Tannins obviously cause astringency.  And starches are attractive to bacteria, which could infect your brew and cause all sorts of strange flavors, likely including the sort of "huskiness" that you are detecting.

Perhaps have too rough a mesh on your grain bag??  You want a super-fine mesh on your bag to prevent grainy stuff from getting to your boil kettle.  You say you don't "filter" at all.  So, if you are getting any chunks of grain and then boiling that, this can definitely cause astringency.  I do BIAB a lot myself, and yes, I have experienced astringency before, which after much research, I was able to attribute definitively to chunky stuff in my boil kettle.  So now what I do is actually recirculate my runnings through the grain bag and a colander.  Basically, pull out the grain bag as normal, but also set it in a colander, which I set onto the boil kettle, then pour the whole mess through the bag again.  It's tedious but effective -- I haven't had any problems with astringency since.  I know another guy who just puts a fine colander into the wort and pulls out chunks that way.  I haven't tried that yet, but I really think it should help a lot.

Yeah, it could be choice of base malt, too.  What are you using?  Any 6-row malt will have a greater chance at both huskiness and astringency.

My wager is on boiling chunks of grain that didn't get strained out.  You really need to get that stuff out of the boil kettle.

[nateo]

"Perhaps have too rough a mesh on your grain bag??"

Now that you mention it, I also switched from cheesecloth bags to poly paint strainer bags, which are a bit coarser. Forgot about that.

" So now what I do is actually recirculate my runnings through the grain bag and a colander."

I like that idea. I'll try that next time I brew.

I'm using high quality 2-row, so I don't think the base malt itself is the issue. It was milled by the maltster, and it has a much higher flour-to-grits ratio than I can get with my 2-roller mill. I assumed the "chunks" I'm getting in the brew kettle were the flour, but it may have little bits of finely ground husk too.

[denny]

I'm trying to pin down when exactly the flavor started, and I think it was about the time I bought my last bag of malt. I've made about 6 batches with malt that was milled by a maltster, instead of my 2-roller mill. The crush is finer than I get on my mill, and extract efficiency is better.

Often times when you buy pre milled malt, the husks gravitate toward the top of the bag while the fines fall to the bottom.  Unless you make an effort to somehow remix it, I think it's possible that you're getting a higher than normal % of husks.  It should go the other way by the time you get to the bottom of the bag.

[Kit B]

Don't squeeze the bag.
Just let it drain, gently.

[denny]

Don't squeeze the bag.
Just let it drain, gently.

I really don't think bag squeezing causes astringency.  Have you found that it does?

[alikocho]

Don't squeeze the bag.
Just let it drain, gently.

I really don't think bag squeezing causes astringency.  Have you found that it does?

I don't use brew in a bag, but I do make fruit jellies. Squeezing can cause some particles to come through, and you can end up with cloudy jelly, so squeezing the bag could result in some grainy bits ending up in the boil I guess.

[denny]

I don't use brew in a bag, but I do make fruit jellies. Squeezing can cause some particles to come through, and you can end up with cloudy jelly, so squeezing the bag could result in some grainy bits ending up in the boil I guess.

While it could, I've never found it to happen when I've tried it.  I'm looking for somebody with personal experience in this so I can find out if my experience is an anomaly.

[richardt]

When I brewed with extracts or partial mash kits that had disappointing results, I'd figured the astringency more likely to be due to oversparging (a common newbie error that I made) and or use of high-alkalinity local water. 

Simply lifting the mesh bag out of the kettle and letting the weight of the wet grains compress against the side of the kettle to encourage draining did not strike me as "excessively squeezing" the steeped grains.

[nateo]

So, I've been thinking, and trying to tease out variables that have changed since I started getting the astringency. I've done 20+ batches of BIAB without this issue, all of varied gravity, with the same techniques (squeezing, water treatment, decoction mashing, etc). To summarize:

1) Switched to a poly paint strainer bag instead of cheesecloth.
2) Switched to pre-milled grain instead of milled-at-home grain.
3) I used to filter out the hops/break material going from the kettle to the fermenter, but haven't recently. Lately I've just dumped it all in, at the advice of quite a few people who say that it doesn't make a difference.

The possible differences that has made are:
1) More small particles getting into the wort. This seems to be confirmed by me seeing more grain bits floating to the top of the wort before the boil really gets going. I skim as much off as I can, but I can't get it all off.
2) More flour in the grist to begin with, so maybe that contributes to the particulates.
3) Maybe the hops in the colander acted as a filter to strain break material and grain bits from the wort.

So of the variables that I know have changed (not including variables I don't know I've changed) it seems that particulate matter in the wort is the most likely culprit. Does this sound correct?

Maybe squeezing the bag can cause astringency in some cases, and maybe I've just gotten really lucky in the past when I haven't had this problem when squeezing. And if squeezing does cause astringency, would it be because of the excessive particulates in the wort, or is there some other factor to this?

On a side-note, can anyone describe the mesh-size difference between cheesecloth and voile? I know my paint strainer bag is coarser than cheesecloth, but I haven't seen voile, and I know that's what most BIAB guys recommend using.

[mabrungard]

I have a difficult time believing that squeezing the grist will cause astringency by itself.  I know of several commercial brewing systems that use press plates that squeeze the grist in the lauter tun to improve extract. 

If the squeezing causes particulates to exit the grist and enter the wort, then I believe that the process could add astingency to the finished beer.  Its the filtering, not the squeezing that needs careful consideration.