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brewzombie 09-12-2012 09:47 PM

Help ID bitter off-flavor (taste like tonic)
 
Hi everyone.

I've have a persistent off-flavor that has plagued my brewing for the last 2 years. It's intensely bitter and lingers on the tongue and throat. I've read the descriptions of off-flavor's and I can't quite fit it into any of the categories. The best description I can give is that it tastes like quinine (tonic water) and sometimes the beer is just unpleasant and sometimes undrinkable.

The most recent casualty is a 40 IBU pale ale that tasted great at bottling, but turned bad after 3-4 weeks in the bottle (conditioned at 19-22 C). This beer an all-grain batch, which mashed/sparged at regular temps. I don't check pH but do monitor temperature. It was fermented 1 week in primary and 3 weeks in secondary (dry hopped 1 week), all at 19-22 C. I try to be careful not to oxidize when autosiphoning during the transfer.

I use campden tablets in my brewing water to neutralize any chlorine/chloramine (I haven't used campden in my sugar-water or starsan solutions...hmm).

I clean my gear/bottles by soaking in PBW, rinse thoroughly and sanitize with starsan (ie there is no chlorine from cleaners etc.).

I bottle by autosiphoning from a carboy to bottles using a plastic bottling wand. The bottling sugar was poured into the carboy (maybe oxidation?) since it's hard to autosiphon 1 cup of bottling sugar.

I've done my best to account for possible culprits like green beer (too young), astringency (hot mash/over sparging), oxidation (splashing hot wort or fermented beer), and chlorophenols (chlorine in water, clearners etc). My last thought is maybe wild yeast, but I try to clean my plastic and have no obvious scratches. I can try really soaking my autosiphon and replacing the tubing and bottling wand, but that's about all I can think of.

Thoughts? Has anyone had a quinine-like off-flavor and eliminated it?

tedclev 09-13-2012 02:01 AM

My vote is that you are underpitching your beers- stressed out yeast can produce some flavors I suppose is similar to quinine now that I think about it- or you do have an infection in your plastic. If you've some sort of wild yeast strain or bacteria hanging out, that will certainly do it. If your beer truly tastes fine at bottling, then it is probably the latter. That being said, it's time to replace your buckets and tubing; you aren't getting rid of those microbes, I don't care how much StarSan you throw at it.

brewzombie 09-13-2012 04:07 AM

I'm leaning towards the infection (wild yeast or bacteria) as I typically use use starter cultures. I really don't want to throw out the autosiphon, but if a PBW soak overnight won't get rid of the bugs, I guess I'll have to. Any chance I can keep my primary bucket? The beer was delicious before touching the bottling equipment.

Petedadink 09-13-2012 01:45 PM

Do you filter your water ? It could be your picking up some alkaline from your water . If you brought up gushing then I'd say infection from your plastic parts and replace those .

brewzombie 09-13-2012 04:18 PM

I don't filter my water, but Vancouver water is super soft and the beers I make are all pale in color. The "predicted" pH for the mash are always in range and I've even used pH 5.2 stabilizer in some batches, with the same result. I've had gushers previously, but not yet on this batch. If it is an infection, I think I slowed it down with controlling the conditioning temp and then going straight to the fridge after 3-4 weeks. Thinking back on the batch before this one, I left them a few months at room temp because they tasted bad (same bitter quinine taste) and I was hoping they'd improve, but many of those did turn into gushers.

cosmo 09-13-2012 06:33 PM

Infection is a possibility, but if you are reasonably careful about sanitation, it is not likely. If you are pitching the correct amount of yeast and controling fermentation temperature, I would look at water and wort oxygenation next. How do you aerate or oxygenate the wort? What is the alkalinity level of your water?

If you are getting gushers and you are not over priming or bottling too soon, then it is infection.

bdh 09-13-2012 07:53 PM

How consistent is the quinine flavor? Is this happening every batch, or just something that pops up now and then? Do you use 5.2 stabilizer in every batch? Any other water treatments besides campden tablets?

If you ask the water gurus over in the brew science forum they'll give you a big list of reasons why 5.2 doesn't work and how it just adds a bunch of salt to the water.

brewzombie 09-13-2012 09:47 PM

Cosmo:
  • I'm reasonably careful about sanitation (I've worked in biochem/microbiology labs), but I admit I could be better about cleaning my tubing and autosiphon with PBW as I usually just flush with water and starsan after use and flush with starsan before use. I usually only use PBW/oxiclean free for the buckets/carboys/bottles.
  • I usually pitch optimal yeast quantities, but I merely used a Wyeast activator smack pack this time...however it was super fresh (by date). The bitter flavour is consistent from batch to batch so I don't think this is the problem. The airlock started going within 12 hrs.
  • Tap water in Vancouver is essentially RO water with a pH 6.5 - 7.2 (depending on the reservoir source).
  • I oxygenate the wort by pouring the chilled wort through a sanitized screen and sealing the primary bucket with a stopper and shaking it on the floor for about 5 min (occasionally opening the stopper to let more air in).
  • I'm not meticulous about bottling sugar quantities but always add 3/4 cup corn sugar for 5-6 gal batches. The gushers don't always happen, but are pretty common when I let the bottles sit at room temp for more than ~2 months or so. They don't necessarily hit the ceiling when they gush, but appear way over carbed.

bdh:
  • The off-flavor is consistent. "Quinine" is the best way I can think of to describe it. It's slightly variable from bottle to bottle, but this batch is one of the more drinkable (barely), which as I said I think may be due to keeping the bottles at 19-22C for 3-4 weeks and then refrigerating. It's in every batch to some extent, often much worse. I've pitched more batches down the drain than you can imagine and still keep trying.
  • I don't use any other water treatments, but have decided to add CaCl2 and CaSO4 in the boil (not mash) next batch to help with yeast health and hop flavour, respectively, and to get the mineral quantities to preferred ranges for a pale ale. I didn't use pH 5.2 stabilizer in this batch but used it religiously for about a year. I've predicted the mash pH in Bru'n water and it was 5.2 for the current batch. I've since adjusted the malt profile to predict a pH 5.4 for the next batch for what's that worth.

Thanks for the replies! This is helpful!

terrapinj 09-13-2012 10:46 PM

i'd try using all RO water for the next batch and use the Water Chemistry Primer as a guide for water treatments

it's the easiest thing to isolate at this point

i would think you'd see/taste other signs of infections if it's happening for every batch for 2 years

ColumbusAmongus 09-14-2012 12:31 AM

Have you tried bleaching everything? I had about 4 batches in a row turn out horrible due to a medicinal / band-aid flavor. I obsessed over chlorophenols coming from my water chlorine but it turned out to be an infection that I think was in my carboy. After bleaching and following the technique of swishing around a rag inside of the carboy, my next batch was free of that horrible flavor / smell.

There is some taboo surrounding bleach but IMO it is a better and cheaper option than buying new equipment and pretty much a sure way to eliminate any infections. Heck, if you are thinking of tossing equipment out anyway, might as well try a round of bleach.


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