Author Topic: astringency  (Read 4887 times)

Offline redzim

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astringency
« on: January 02, 2013, 06:25:56 AM »
I've been noticing a little astringency (dry puckery aftertaste that lasts a little too long for my liking) in only a few of my beers this past 6 months.  After looking thru my brewing notes I noticed that this flavor was pretty much confined to high-attenuating, medium-bittered amber-ish beers (ales & lagers). Here's my theory, you tell me if I'm on the right track:

I think I've been sparging with too-hot water (I batch sparge a la Denny).   Somewhere a while ago I read that one should sparge with 180F water but I'm kind of sloppy about it and often hit 185 or 190 (I log this every batch.)  I then often hit a mash-tun temp of 175+ before I start running off my second runnings (but I only leave the mash at that temp for 5 mins, max).  Now searching online for sources of astringency, I find a lot of people saying that sparge water should not be above 170F...  Which I definitely have not been heeding...  So how possible is it that this hot sparge is extracting tannins?

I think I am doing this for all my beers but my theory is that I only notice it in certain beers like Alt and Oktoberfest because they finish out pretty dry (~1.010) and are not aggressively hopped.... in my recent Pilsners, Pale Ales, and IPAs I have not noticed this because they have a lot more hops in. Also in other slightly " sweeter" beers like Porters and Bocks I don't notice it because of more malty flavors, higher F.G., etc.   Is this a good guess?

Also: is it worth checking the pH of the mash at sparging time? Currently I only check the mash about 5-10 minutes into the first rest, I aim for around 5.3 to 5.6 (at room temp) and pretty much get there all the time... but I do boil in a large-diameter steam kettle and need to collect 16 gallons of liquid to boil down to 11 gal of wort; I often run-off only 6.5-7 gallons of first runnings, and then sparge with 9+ gallons more; could this by somehow messing up the pH of the sparge by diluting the buffering power of the grain and making the mash pH jump up to 5.8 or higher?

One more thing could be that I'm milling too fine... is it true that too much "flour" in the grist will extract tannins? I'm using a BarleyCrusher set on about 30-32 mil (measured with an automotive feeler gauge) but I do see a fair bit of flour.... my brewhouse efficiency usually hits around 85%; lower for 1.060+ beers, but I do hit 90% on some decocted or low-gravity brews. 

thanks
red

(edited to correct misspelling in post title)
« Last Edit: January 02, 2013, 09:33:48 AM by redzim »

Offline hopfenundmalz

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Re: atringency
« Reply #1 on: January 02, 2013, 06:36:36 AM »
Red - I acidify may sparge water to 5.5 or so. Remember that when you do a decoction the grains are boiled at mash pH and you don't get high astringency.

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Offline tygo

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Re: atringency
« Reply #2 on: January 02, 2013, 08:22:04 AM »
Red - I acidify may sparge water to 5.5 or so.

Same here and I think this could be your problem.  The combination of high temperature and relatively high alkalinity is what causes tannin extraction.  If your sparge water is below 5.7 or so the temperature is less important.

I had the exact same astringency issue awhile back and it went away once I started acidifying my sparge water.  I routinely sparge at temperatures greater than 170F.
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Offline beersk

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Re: atringency
« Reply #3 on: January 02, 2013, 08:27:17 AM »
Maybe you're over sparging too if you're collecting 5 more gallons than you end up with...
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Offline nateo

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Re: atringency
« Reply #4 on: January 02, 2013, 09:16:19 AM »
Back when I was doing BIAB, I had a run of like 6 or 7 heavily astringent beers. I traced it back to when I switched from a fine mesh to a coarse mesh bag. I always sparged with water under 160*F and under 6 pH. Theoretically, there was no way for me to extract tannins that way. But I switched back to a fine mesh, and the problem was solved. So I think if you get a lot of draff into your kettle and fermentor, that can cause astringent-type off-flavors.

Now that I have a proper MLT, I get my wort as clear as possible, though sometimes it's a little cloudy.

If you're batch sparging with water that's 180*+, it'll raise the temp of the grain bed, so I doubt your run-off is actually over 170*F.
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Offline beersk

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Re: atringency
« Reply #5 on: January 02, 2013, 09:20:39 AM »


If you're batch sparging with water that's 180*+, it'll raise the temp of the grain bed, so I doubt your run-off is actually over 170*F.
This is what I was thinking, which led me to think he's over sparging.  But he did say that he took temperature readings of 175F+.
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Offline redzim

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Re: atringency
« Reply #6 on: January 02, 2013, 09:25:34 AM »
Red - I acidify may sparge water to 5.5 or so.

Same here and I think this could be your problem.  The combination of high temperature and relatively high alkalinity is what causes tannin extraction.  If your sparge water is below 5.7 or so the temperature is less important.

I had the exact same astringency issue awhile back and it went away once I started acidifying my sparge water.  I routinely sparge at temperatures greater than 170F.

So how do I acidify sparge water? I've never done that... any tips on formulas & chemicals would be appreciated... my tap water is around 7.5-7.8 pH, but on some brews I use 50% or more (up to 100%) distilled water with some minerals added in....  I guess the pH of that water will still be at least 7 or more though, as distilled water has pH of 7, right?


Offline redzim

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Re: atringency
« Reply #7 on: January 02, 2013, 09:31:46 AM »


If you're batch sparging with water that's 180*+, it'll raise the temp of the grain bed, so I doubt your run-off is actually over 170*F.
This is what I was thinking, which led me to think he's over sparging.  But he did say that he took temperature readings of 175F+.

Ok so how do I stop "oversparging"....  try to balance my first run-off and 2nd run-off?

For instance on the Altbier I'm drinking right now, which got me thinking about this, I ran off 6.0 gal, then sparged to collect another 11.5gal to reach 17.5 gal, which I needed because I wanted to do a 75 minute boil....  I guess that is pretty unbalanced, and I could mash a lot thinner to get that balanced out (I doughed-in at 1.5 qts/lbs, then did an step infusion to get my sach rest, this left the mash at 2.15 qts/lbs, then I did a decoction mashout). 

My 2012 Oktoberfest was more balanced in the run-offs; I collected 7 gal first, then sparged 9 gal more to get 16 gal total which is all I needed for a 60min boil.  Still had a mildly unpleasant astrigency about it....

Offline beersk

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Re: astringency
« Reply #8 on: January 02, 2013, 10:24:37 AM »
Why are you collecting so much if you're only ending up with 11 gallons in the fermenters? Do you have a ridiculous boil off rate?
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Offline hopfenundmalz

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Re: atringency
« Reply #9 on: January 02, 2013, 10:25:55 AM »
Red - I acidify may sparge water to 5.5 or so.

Same here and I think this could be your problem.  The combination of high temperature and relatively high alkalinity is what causes tannin extraction.  If your sparge water is below 5.7 or so the temperature is less important.

I had the exact same astringency issue awhile back and it went away once I started acidifying my sparge water.  I routinely sparge at temperatures greater than 170F.

So how do I acidify sparge water? I've never done that... any tips on formulas & chemicals would be appreciated... my tap water is around 7.5-7.8 pH, but on some brews I use 50% or more (up to 100%) distilled water with some minerals added in....  I guess the pH of that water will still be at least 7 or more though, as distilled water has pH of 7, right?

I use lactic or phosphoric acid, check with the pH meter. If distilled absorbs CO2, you get carbonic acid that drops the pH.

Brunwater can do the calculations.
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Offline mabrungard

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Re: astringency
« Reply #10 on: January 02, 2013, 11:03:50 AM »
I have another theory on astringency in wort and beer.  With the make up of Red's water, this may be a candidate.

Tannins are the predominant cause of astringency in brewing.  They are complex organic molecules that can complex with metal ions and precipitate out of solution.  They also complex with proteins. 

For the past several years, I was confused as to why my morning cup of tea tasted better at work than at home.  At home I have RO water in the kitchen and at work I have typical Midwestern hard water.  On the outset, I assumed that RO water would make better tea since it has very little alkalinity.  But invariably, the tea made with the hard tap water was smoother and less astringent even though they are otherwise identical (temp, teabag, etc). 

The other week I was reminded of the fact that tannins and metal ions will complex and then it hit me that was what was missing in the RO water.  So, I did a quick and unscientific experiment to see if adding calcium to my RO water would make better tasting tea.  Before adding the teabag, I dropped in a few pearls of calcium chloride to see if I thought there was a taste improvement.  In my opinion, there was! 

With this unscientific result, I now need to perform a more scientific analysis of this effect and its perceptions.  Calcium chloride is the obvious choice since calcium is moderately flavorless.  Gypsum is a candidate, but sulfate introduces its own flavor.   Chalk doesn't dissolve adequately, so its out.  Magnesium is out too since it adds too much flavor at high concentrations.  I figure I'll mix up a couple of CaCl solutions and brew up some strong teas.  With some triangle testing with a few subjects, I should be able to discern a cause and effect. 

So in Red's case, I think that the calcium content of his brewing water may have been too low to remove much of the tannin that is naturally present in wort. I look forward to hearing what Red has to say with regard to his typical mashing and sparging water calcium content. 

By the way, Polyclar will precipitate tannins too.     
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Offline redzim

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Re: astringency
« Reply #11 on: January 02, 2013, 12:54:50 PM »
Why are you collecting so much if you're only ending up with 11 gallons in the fermenters? Do you have a ridiculous boil off rate?

Yes I do!  As stated earlier, I have a large diameter (26") steam jacketed kettle... spherical bottom, so with 11 gals of  liquid in there it's still only about 11" deep....  I try to boil off as gently as possible but.... in a 60 minute boil I still loose about 5 gallons to evaporation.

Offline redzim

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Re: astringency
« Reply #12 on: January 02, 2013, 01:10:36 PM »

So in Red's case, I think that the calcium content of his brewing water may have been too low to remove much of the tannin that is naturally present in wort. I look forward to hearing what Red has to say with regard to his typical mashing and sparging water calcium content. 

By the way, Polyclar will precipitate tannins too.   

Here are some calcium numbers from my brews: (Let me know if you need more numbers)

My regular water has 56ppm Ca, alkalinity of 142ppm. I use this for my Altbier.

My Oktoberfest water was diluted 50/50 with distilled, & I added CaCl and gypsum back in to get 54ppm Ca and 75 ppm alkalinity.

For German Pilsners I start with 100% distilled and add in CaCl, epsom, and gypsum to get to 58ppm Ca and 0 ppm alkalinity.

For the most part, most of my beers are around 50-60ppm Ca in the water. I use same water for mash & sparge. I'm going to take a look at acidifying the sparge water. I have some questions about using BrunWater to do that; I will PM some questions to you.

-red




Offline dmtaylor

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Re: astringency
« Reply #13 on: January 02, 2013, 01:15:07 PM »
 :o  That boiloff rate is insane!  Here's a theory: You aren't getting any more tannins in your runnings or sparges than anyone else.  But what you *are* doing is you are concentrating the tannins way down, more than any other homebrewer, and so this is part of the reason you're picking it up in your beers when you wouldn't normally expect it.  Also, since you need to sparge so darn much to get up to your boil volume, you could indeed be oversparging, which is also leaching out more tannins.  Your high efficiency of 85-90+% is also reflective of oversparging and boiling too hard.  So here's a thought: Don't boil so dang hard, or consider boiling with the lid on so you don't lose as much volume during the boil.

Of course, I'm sure the pH and high temperature sparge also have something to do with it.  When you fix all of these issues, whatever it takes, then you'll lose the astringency.
Dave

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Offline redzim

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Re: astringency
« Reply #14 on: January 02, 2013, 01:22:57 PM »
:o  That boiloff rate is insane! 

I like your theory....  what typical boil-off rates are you guys getting? Or to put it another way, how much liquid are you guys starting with, to end up with 10.5 or 11 gals into the fermenter?  Obviously not 16gals...