What can I do about astringent aftertaste with all-grain?

I recently started brewing all-grain. For years I've brewed with extract and made some really good beers. Now, I've made half a dozen batches all-grain and every single batch has had a real astringent aftertaste, not related to hops. I'm using a large rectangular cooler with a bazooka screen, Brewsmith software, and usually a single infusion, no-sparge mashing technique. Every batch has gone very smoothly, hitting all my target temps and gravities spot on. I read and studied all-grain method a long time before actually attempting it, laying it out clearly in my mind what I was going to do, so I felt very comfortable when doing it. The bad aftertaste must be coming from the mashing process, but I really don't know where or what I could do to avoid this. Anybody have any ideas?

Hi, the first thing I'd look at is your grain crush.  Over crushing grain can cause astringency.  I have my mill gap set to .037 inches.

Next, make sure you don't over sparge, do not parge with boiling water and ensure water isn't overly alkaline.

Finally, oxidation during fermentation.

Mark

Crushing the grain too fine will cause stuck sparges, but you've been doing "no sparge" batches, so I'd look at your water ph, and doing a long enough boil. Other things that may be causing it is introducing oxygen into the wort while it's still too hot. Since you've been doing extracts brews for awhile I'm guessing it's one of those two things.

Mash pH, not water pH, is what matters. That would be my top suspect.

Myk said:

Mash pH, not water pH, is what matters. That would be my top suspect.

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I should have said mash ph, the amount and type of grains you use will dictate the mash ph for the most part. Revbish, what is your water source?

I have had the same problem and I think i know what the problem is. Astringency i probably caused by Mash-pH being too high. It will cause bad tasting tannins to extract from the husks. It will only be a problem with light to amber beers. Never a problem with stouts/porter because the dark malts produce a lot of acid.
If you have a relatively high level of HCO3 (bicarbonate) and Calcium your water will be hard and you need to soften it. The easy way is to boil it with will make CO2 leave the water causing most of the bicarbonate and calcium to sediment to the sides and bottom of your pot. Cool the water and more will sediment, but keep the lid on so CO2 from the air does not get in to your water lowering the pH and dissolving part of the chalk (CaCo3) again. Also the remaining Calcium in your water react with grain phytins and lower your pH. Don't use too much mash water, the dough-in is easier but it will raise your pH, and there's your risk of astringency again - not a problem if your dark beers. 
Please use John Palmer nomograph efter getting your local water report (howtobrew chapter 15) I have attached my own. Red lines are results after boiling.
Also read "Decarbonation By boiling on this absolutely splendid page: https://sites.google.com/site/brunwater/water-knowledge

From what I've read temps above 180 can extract tannins from the husks, though I've never experienced it myself.

revbish said:

I'm using a large rectangular cooler with a bazooka screen, Brewsmith software, and usually a single infusion, no-sparge mashing technique.

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Single-infusion, no-sparge........meaning you fill it once and drain it once?  How many pounds of grain do you use for 5 gallon batch? 

That method would eliminate sparging too hot or too long, so extremely alkaline water seems likely. 

Of the six batches, were any darker brews (SRM > 23) and they still were astringent?  If so, that would point back toward too hot, since a darker brew should have been better suited to the higher pH, as others pointed out.  Have you calibrated the thermometer you're using?

A $17 water test from www.wardlab.com may be needed, and/or a pH meter to verify the water.  You could try a batch with purchased distilled water and see what happens.

http://www.wardlab.com/FeeSchedule/WaterAnalysis.aspx  Test W-6

This is the second posting I've seen Wardlabs.com recommended for a $17 water sample test. They're probably both from you ... and I appreciate the notion. However, I went there and didn't see any mention of water testing. The closest was a microbiology lab at U of Wyoming. Can you please check that out again? Perhaps their URL has changed.

https://producers.wardlab.com/BrewersKitOrder.aspx

http://www.wardlab.com/FeeSchedule/WaterAnalysis.aspx

Interesting.  They are getting an extra $9.50 with their mailing kit aimed at homebrewers.  The same W-6 test is $16.50 if you just send them a water bottle.  A flat-rate box from USPS would be $5.00.  (I checked into local labs here and they wanted over a $100 for the same testing.) 

Either way, it's very helpful to know your base water character.  It varies quite a bit around here (Charlotte) and even more just hours away in Raleigh.  And we're lucky with low-mineral water; if you live somewhere and one mineral (or pH) is crazy high, then you may wish to cut your water with distilled. 


Back to the astringency.........are you absolutely certain it is astringent, and not some other off-character?  You're getting that drying, tea-bag tightening sensation across your gums or somewhere else in your mouth?  Like dry red wine can be?  Astringency is more a mouthfeel issue than a flavor per se.  Just wanted to confirm we're chasing the right thing.

Thanks for the Ward Labs URL extension. That will give me something to compare after submitting quotes from local SoCal labs. Interesting to see how some of these sites are promoting their services to take advantage of the fracking hysteria. I've personally never tried to light my wort on fire.

Jens W, interesting water site. Thanks for the link!
Regards,
Slurk

i was having the same problem.  got a water report from the city and the bicarbonate is through the roof.  now i use 50/50 tap and distilled for the mash and the last 5 batches had no off flavors.