BITTER aftertaste - What's going on?

[brighamj]

The past two batches that I've brewed have been with different yeasts and different recipes. Each aged out properly (3+ weeks) before I kegged them. Each also has the same harsh bitter aftertaste -- even after 2+ weeks in the keg. I am pretty damn sanitary in my process, and I question whether or not this could be the issue, but I have no idea what other options there could be.

I am all grain, with temperature regulated mash and sparge, ferment in glass carboys at a fixed temperature (to the degree), always boil my chiller before knocking out, and on a whole am very, very sanitary.

My thoughts are a rogue yeast, but how? Through the blowoff tube? What about the positive pressure from the CO2? Can a nasty make it up the tubing?

Temperature probes may be off? They are Ranco units. I haven't yet tested them, but my efficiency is on point, so I don't think they are erring on the high side, and isn't this the side where tannins may come from?

Something to do with water chemistry? I'm on a well and haven't tested it in awhile. I've read that Magnesium can be a culprit, but the last time I checked mine was only 6ppm.

Other than that, I'm at a loss. It's a pretty pronounced, flavorless bitterness, and these batches have really suffered for it.

Thanks in advance, guys. I know it's hard to diagnose something like this, but I'm interested in your thoughts!

 

[Wynne-R]

Astringent: Mouth-puckering, lingering harshness, husk-like graininess Don't oversparge. Don't overcrush grain. Don't boil grain. Don't sparge with water above 170°F. Don't sparge with water with a high pH (over 6). Use water with lower sulfate content. Use less dark grains (especially black malt). Use less whole hops (especially high-alpha hops or simply large quantities of hops). Avoid use of raw spices, fruit pith and fruit skins. -http://www.bjcp.org/faults.php

http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/

Sounds like tannin. Try adding some acid to the sparge water or using RO water.

 

[brighamj]

http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/

Sounds like tannin. Try adding some acid to the sparge water or using RO water.

I hit all of those marks. Sparge is 168. pH for Mash and Sparge are always between 5.5 and 5.8 depending on how much dark grain I use. It's a HERMS system, so the grain doesn't get too hot. I think it's either water chemistry, although that would be a huge spike upwards, or a contamination issue. To be on the safe side, I spent the past few hours stripping everything part -- every fitting, valve, disconnect, etc. They are all in a cleaning bath now, then they'll spend some time in the dishwasher to pay for what they may have done.

 

[brettg20]

What is your recipe / what yeast did you use?

 

[LovesIPA]

It sounds similar to what happened to me a few months ago. The welding shop I get my CO2 from deals with a lot of wineries and breweries, both home and commercial. It's not uncommon for a CO2 tank to be returned to the shop with some beer or wine in the tank. Since it's a liquid at room temperature it never leaves the tank. When the beer or wine spoils eventually, it will taint the gas and anything you carbonate with the gas doesn't taste right at all.

If you're confident in your sanitation, disconnect the tank and VERY carefully crack the valve open. CO2 smells acrid and it will burn your nose a little but it shouldn't smell like much of anything. If you have two tanks, even better because you can just compare the odors. In my case, the contaminated tank smelled very different from a clean one. I changed the tank out and no more problems.

 

[brighamj]

It sounds similar to what happened to me a few months ago. The welding shop I get my CO2 from deals with a lot of wineries and breweries, both home and commercial. It's not uncommon for a CO2 tank to be returned to the shop with some beer or wine in the tank. Since it's a liquid at room temperature it never leaves the tank. When the beer or wine spoils eventually, it will taint the gas and anything you carbonate with the gas doesn't taste right at all.

If you're confident in your sanitation, disconnect the tank and VERY carefully crack the valve open. CO2 smells acrid and it will burn your nose a little but it shouldn't smell like much of anything. If you have two tanks, even better because you can just compare the odors. In my case, the contaminated tank smelled very different from a clean one. I changed the tank out and no more problems.

I'd heard about this happening. I'll grab a second tank and compare. However, I've had a few batches carbed out of the current one without any issue.

As to the recipes. Different base malts, different specialties, an American yeast and an English strain.

The whole thing has really been bothering me today. On the upside, all of the gear is now sparkling clean.

 

[brewguyver]

Wild yeast or old beer yeast could get in the air tubing if you don't have a check valve that prevents it. However I don't see you getting a bitter flavor from that - it would be sour/tart, acidic/vinegar, or a spoiled flavor.

I used to get a bitter flavor off force kegging a lot, and I tied it finally to overcarbing. CO2 creates carbonic acid when dissolved into a liquid, and that can result in a harsh/bitter flavor. The good news is that it comes out of solution immediately if the pressure is reduced. So check your pressure/temp to see if too much dissolved CO2 could be your problem.

 

[brighamj]

I actually have a theory as to what may have happened. If I'm right, it is all operator error.

I brew on a single tier, three kettle set-up. When I'm done with my saccharification rest and I bring the temp up to the high 160's for the mashout, I think I may have adopted the possibly bad habit of turning the burner on under the mash kettle. I am unsure if I did this on all of the bad batches or not -- bad memory. I know I did on at least one.

My thought is that by using the burner in conjunction with the HERMS, in an effort to raise the temperature more quickly, I may be raising the temperature of the bottom of the grain bed to a level where tannins are being extracted.

There is 1.5" between the bottom of the kettle and the false bottom (bottom of the grain bed), with a single exit point for the mash. If there are any "eddies" in this bottom layer, it may explain the heat differential.

The temperature probe is inches above the false bottom, and perhaps there are in fact layers of heat differential.

Any thoughts?

 

[brighamj]

Wild yeast or old beer yeast could get in the air tubing if you don't have a check valve that prevents it. However I don't see you getting a bitter flavor from that - it would be sour/tart, acidic/vinegar, or a spoiled flavor.

I used to get a bitter flavor off force kegging a lot, and I tied it finally to overcarbing. CO2 creates carbonic acid when dissolved into a liquid, and that can result in a harsh/bitter flavor. The good news is that it comes out of solution immediately if the pressure is reduced. So check your pressure/temp to see if too much dissolved CO2 could be your problem.

I haven't heard of bitter from yeast, either. I always have thought sour, bandaids and/or funk.

 

[anico4704]

I would try building some RO water from scratch, sounds like a water issue to me .

 

[brewguyver]

I actually have a theory as to what may have happened. If I'm right, it is all operator error.

I brew on a single tier, three kettle set-up. When I'm done with my saccharification rest and I bring the temp up to the high 160's for the mashout, I think I may have adopted the possibly bad habit of turning the burner on under the mash kettle. I am unsure if I did this on all of the bad batches or not -- bad memory. I know I did on at least one.

My thought is that by using the burner in conjunction with the HERMS, in an effort to raise the temperature more quickly, I may be raising the temperature of the bottom of the grain bed to a level where tannins are being extracted.

There is 1.5" between the bottom of the kettle and the false bottom (bottom of the grain bed), with a single exit point for the mash. If there are any "eddies" in this bottom layer, it may explain the heat differential.

The temperature probe is inches above the false bottom, and perhaps there are in fact layers of heat differential.

Any thoughts?

If it's tannins, that would completely depend on water PH and potentially be due to over-sparging. If it was heat alone could leach tannins, then decoction mashing (where you pull off some grain/liquid and boil it, then return to the mash) would result in heavily tannic, astringent beers instead of the rich malty hoffbrau haus beers. So if tannins are the problem, it was probably that your sparge water wasn't acidic enough to compensate for reduced acidity in the mash post pulling first runnings.

You may have also scorched the wort, but that would give a burnt bitterness which you'd probably be able to taste.

Other than that, the double heating sounds like a reasonable approach.

I would try building some RO water from scratch, sounds like a water issue to me .

^ This from a sparge water perspective.