Mysterious off-flavor...

Gang: I have a couple of beers that were made in the past few months that have a very sharp, harsh finish. The beers look good, smell good and taste good until you swallow and you get this really dry & sharp finish on your tastebuds. I had an issue once where my water filter cartridge coughed up everything it had previously filtered and it left a harsh flavor in a number of beers but that it not the issue here. I just filtered some water this morning and it tasted very good. The beers in question are a blonde ale made with 1272, a red lager made with 2308 and a Czech Pils made with 2278. All of these were made with some amount of distilled water to cut my bicarb and in between all of these I have made some outstanding beers including a West Coast Lager, a Mexican Dark Lager, an ESB and an "Extra Pale Ale" made with 2112, 2124, 1968 and 1056 respectively. I have been brewing for 14 years and just got my first mill last year. Does anyone think I could be sending my grains through the mill too quickly with my drill and doing too fine of a crush and bringing out tannins? My crush does not seem pulverized and I have not had any stuck runoffs. Plus, there are these other beers that have been stellar. I mentioned that these beers were "astringent" to members of another board but they thought my description was something other than astringency. Also, these are relatively low-IBU beers... anywhere from 25 to 40 maybe. Has anyone experienced this? Thanks Beerheads.

Is it plastic / bandaid like? Phenols can taste pretty dry / sharp / harsh.

Where is your water coming from? If its from a municipal source, its possible they've changed up the chemicals or amounts of chemicals depending on what they are treating.

I noticed my municipal water sometimes has enough chlorine to bring tears to my eyes. I filter with activated charcoal and use campden tablets to blow off chloromine.

While my experience was with extract, I had a similar issue with an ESB. It had a sharp astringent taste in the finish. This was only perceptible at bottling time and at a week into bottle conditioning. The phenomenon disappeared after 3 weeks in the bottle.

I decided that the cause was my water temp when steeping my grains. It was just below 170, which was due to my not paying attention properly.

Anyway, my vote is for tannin extraction.

My water is Lake Michigan water and I have had it tested numerous times and it's always right in the same zip code for all the numbers. Also, many other brewers from the Chicago and Milwaukee areas have had their water tested and the numbers are the same. Chlorine is high so I filter it through a carbon block filter.

This issue doesn't really have a 'flavor' so my thread title might be misleading. The beer actually tastes great it's just this sharpness on the back of your tongue when you swallow it.

The hops we're talking about here were all pretty clean hops: Tradition, Mt. Hood, Northern Brewer, Hallertau Mittelfruh, Saaz, Hersbrucker. As far as the pH goes, I do use the ColorpHast strips and I shoot for about 5.0 which translates to 5.3 with the built-in autocorrect factor or whatever you want to call it. Typically my water, grains and additions of CaCl or gypsum would be enough to have me very much in the right zip code but if I'm slightly high, I will add very small amounts of lactic acid (literally drops from a syringe-type dropper) to adjust downward. So here is something interesting... I just went and checked my notes on all three of these beers. On the Red Lager and the Czech Lager, under the spot on my worksheet where I record all of the mash info (start time, temp, pH, etc.) under "mash ph" I wrote down "slightly low?" which suggested the ColorpHast strip showed lower than 5.0 which would be less than 5.3. Both of those beers showed "slightly low?". On the blonde ale I just tapped yesterday, under "mash ph" I wrote "slightly high, added 1ml of lactic acid". So I have 2 thoughts. One is obvious... would a low mash pH lead to this flavor? The other came to mind first but doesn't seem relevant now... does lactic acid have a shelf life? Mine is in a small bottle (4 oz?) that I have had for at least 2 or 3 years, easily. I didn't use lactic acid on the other two beers so this may be out the window. I'm brewing today (an American Wheat with an SRM of only 3-4) so I guess I better watch my step. Thoughts?

Low PH wouldn't cause tannin extraction. High PHs are more likely to extract tannin.