Astringent overly bitter lingering taste

[brick_haus]

I haven't seen anything on this subject so I thought I would open this discussion. Let us know your findings/experience and opinions.

This all started when I kept getting this strong bitterness and astringency in almost all of my beers, no matter what I did to avoid it. I was fine tuning my grain crush to avoid shredded husks, carefully watching sparge water temps to avoid tannin extraction, water chemistry... anything I could read on the subject of astringency and beer I read and tried, to no avail. Then (FINALLY!) I ventured off to look for this perceived taste in general, not related to beer...I found several articles and dissertations that came to the same conclusion, copper in solution (dissolved) is characterized by a strong bitter taste and astringency.

My cooling process included running the wort through a plate chiller cooled by hose/tap water, then running it through a copper immersion chiller submersed in ice water. I'm thinking that the low pH wort is bringing some copper into solution causing the astringency. This last batch, I switched to a stainless immersion chiller, so we will see...

Note: I have won a competition or two including one BOS (35-39 points) with only one comment about the "lingering" bitterness. To me it is very apparent, my wife cannot perceive it. It seems to depend on ones palate.

So what do you think? I always circulate PBW solution and sanitize the copper tubing after use and sanitize again before use. Starsan is also acid and may contribute to the dissolution.

 

[trentm]

I think you are barking up the wrong tree. Copper has been used in brewing for eons. I too had problems with a slight astringency and solved it by making sure my final runnings did not go below 1.010. Also, since I've been using more Chloride (60ppm) and less Sulfate (15ppm) the hops (noble) are much softer and the beer has better malt character. These are pale Belgians. I use a 35' copper counterflow chiller.

 

[brick_haus]

I kind of thought that's what people would think. But something has to be causing this. Here is an example of my most recent brew that had the worst case of this bitterness to Date.
All RO water w/2gpg gypsum and 0.5gpg CaCl2(mash only)
Mash pH 5.3
Final running a 1.020
Pre boil 1.052
SG 1.068
FG 1.011
Mash temp 150 (HERMS)
No mash out
170* sparge water temp (on the fly)
Bittering hops
4oz. Columbus 90
1.5 oz. Columbus 45
No more hops until flame out/WP.

QUICKLY cooled to 65*pitching temp (yeast starter was 65 also)
Fermented in chamber at 166*

 

[mabrungard]

You are adding a significant amount of gyp and CaCl to the water. In addition, I suggest that you review the percentage of boil-off that you are producing. If you are boiling off more than about 15% of the original starting wort volume, you are overconcentrating the mineralization and that can create poor flavor.

 

[brick_haus]

You are adding a significant amount of gyp and CaCl to the water. In addition, I suggest that you review the percentage of boil-off that you are producing. If you are boiling off more than about 15% of the original starting wort volume, you are overconcentrating the mineralization and that can create poor flavor.

I can double check, but I'm pretty sure that I am designing the water within recommended mineral content in the Bru N' Water spreadsheet, and I am not treating the sparge water.
I do however boil off more than 15%, more like 20-22%. That's making me think, I had a batch come out REALLY good and astringency free. On this particular batch, I was trying out natural gas rather than propane (nozzles changed!) and could hardly keep a slow boil going. This of course affected the BO rate...This is the beer that won BOS at Ventura County Fair...

Thanks for the advice!

 

[mabrungard]

Your sulfate and chloride additions that you mentioned, seem to produce a fairly high concentration of those ions by my calculations. If the boil off is more significant than the typical 10 to 15%, then the ending concentrations in the final wort could be over the top and that might be creating the off flavors you cite. Dial back either the boil vigor or the starting ion concentrations and see what that does for you.

 

[brick_haus]

Thanks, I'm going to back off on the salts. I actually have a batch in my small fermenter where I did exactly that.

 

[Walfy10]

I've had quite a few problems with astringency at least three batches so far. I can attribute this to over sparging . I've kept a closer eye on my SG and pH towards the end of lautering but still my last homebrew was astringent. The last brew I did was a stout and my only guess was I used a thinner mash with a water/ grist ratio of about 2 quarts/lb and I should have used less sparge water. I usually stop sparging when my pH is ~ 5.8 and SG 1.009. I may try to stop at a higher SG. One thing I would like to note is polyclar as a fining agent is great at removing tannins/astringency though and this has saved a few batches for me.

 

[mabrungard]

I found that I have to stop sparging when the runoff gravity reaches 1.012. That often means that there is a gallon or two of sparging water that hasn't been through the mash. I end up using that water to top up the kettle to provide my desired pre-boil volume. My efficiency is often in the high 80's to 90%. I typically mash at a 1.5 qt/lb ratio. Don't be afraid to stop your sparge early if the gravity falls too low. Low gravity is the primary factor in tannin and silicate extraction. Those compounds are not extracted when the gravity is high unless the pH is WAY too high. As long as you are treating your mashing and sparging water properly, its the low gravity that you need to be vigilant about.

 

[TheMadKing]

Did you ever find a solution to this issue? I have been having the same sort of lingering bitterness and I suspect my salt additions. I do BIAB full volume mash with no sparge and have been cutting 50/50 with RO water and adding 2-4 g gypsum and 2-3 g CaCl to the entire 6.8 gallon mash.