I have been trying to nail down an underlying taste in my brews. It can be slighty tannic/astringent and is more pronounced when burping.
I:
Carbon filter municiapl water and treat with campden
Never go above 168F when sparging
Mash in a voile bag (no grain/husk solids transferred from tun to kettle)
Hop in a 200 micron bag (no hop solids transferred from kettle to fermenter)
Suck the kettle dry and take most of the break material with it
Leave StarSan in my plate chiller for 30-45 minutes before use (no rinse - just dump StarSan and use)
Beer remains in the carboy for 3 to 4 weeks (temperature controlled @ 60 to 65 degrees F)
If not careful, transfer some yeast/trub from the fermenter to the keg.
My beers are clear but always have that underlying tannic taste.
I am wondering if the sediment transfer into the keg is the root of the problem. Tasing the yeasty trub from the carboy, it does taste somewhat tannic.
Doubt the trub will give you any sort of tannin/astringency. Do you know what your pH is when mashing? If that’s off, that would seem to be more likely to contribute those and, in your procedures, you don’t say anything about pH. Also, do you get more/less with lighter/darker brews?
Mash pH and water chemistry come to mind. Have you ever had your water checked? A mash pH > 6.0 will extract tannins from the grain husks. A water relatively high in sulphate will lend a harsh hop bitterness.
If you use RO water just keep in mind that it is free of salts and minerals, so you’ll have to supplement your water with some additional salts depending on the beer style you’re trying to achieve. You can use pH strips at a minimum to check your mash pH. I use a pH meter but strips will suffice. You must ensure that you maintain a mash pH of 5.2-5.7 range during the mash. This will allow for proper enzyme activity and keep the tannins in check. pH strips can be purchased at your LHBS.
Yeah- mineral free water actually compounds the problem when mashing. For now I’d go buy some “Spring water” and mash with that. It’ll taste good and will have minerals in it. Usually the company has water reports online associated with each type of water they sell- at least Ozarka does for example.
Your water utility doesn’t give the right information- you need mineral/salts content and they are providing other info that they believe concerns citizens, but not brewers! ;D
RO has made a big difference to my beers. I get it from Walmart too. You just have to add salts. My standard is calcium chloride for malty beers, gypsum for hoppy beers, and chalk for dark beers. I always add a pinch of epsoms and sea salts for flavor and to supply needed micronutrients. That and I use a nutrient blend in the wort, I believe it has some zinc.
You could always dilute your water 50:50 with RO. I’d agree with the suggestion to have a water test, otherwise you’re kind of flying blind.