Off Flavor (Metallic / Tannic )

[kavan]

Hello!

Long time homebrewer, first time poster here. I've recently run into an issues with my APAs and IPAs producing a harsh bitterness (tannic) with a subtle metallic flavor in the finish. I first noticed this as I played around with my water chemistry. So naturally I fiddled with it more, but now I'm unable to adjust any portion of my water chemistry without detecting both of these off flavors. Naturally, I could just go back to brewing with my untouched water profile, but I much rather get to the bottom of the issue.

So I am hoping you might be able to help!

This is my water profile (Boston, MA MWRA) we are supplied with monthy reports.

Ca 4.1
Mg .9
Na 32.7
HCO3 47.3
CO3 .5
SO4 6.1
Cl 23.4

reported CaCO3 39.7
Measured water PH 8.4
(PH is reported 9.7 at the treatment facility but I've never gotten a reading this high)

So I brewed up a 3.5 gallon batch the other week. I was reading that water adjustments can get super concentrated with these small batches, so I went light with the additions:

Mashing Water Profile (ppm)
Ca 117 ( I realize this is a little high, maybe my first culprit?)
Mg 14
Na 33
HCO3 48
SO4 146
Cl 158

MASH (2.5 Gallons)
150F 60 mins
.6g Gypsum
.8g Calcium Chloride
.5g E Salt

I didn't treat the sparge water.
Batch Sparged 170F
(3.5 Gallons)

Here is the IPA recipe:
(This was a 3.5 gallon batch)
4.75 US 2 Row
1.25 White Wheat
.75 Carapils
.5 Flaked Oats
.25 Crystal 20

.1oz Columbus (16.6AA) 60mins
.5oz Mosaic (11.3 AA) 180F WP 20mins
.3oz Columbus (16.6AA) 180F WP 20mins
.3 Centennial (9AA) 180F WP 20mins
.4 Falconers Flight (11.3AA) 180F WP 20mins

1318 2X gen

4/2 - Brewed cooled to 65F
4/8 - Moved to purged keg w/3oz hops
4/12 - Moved to purged serving keg

OG 1.068
FG 1.014

1st Runnings PH: 5.21
Final Pre-Boil PH: 5.4
Collected Volume: 4.5 Gal

Any help would be appreciated. I keep decent notes, so if I omitted something let me know and I can add it.

Thanks!

 

[cswis86]

I think you're on the right track about it being high mineral content. I would try cutting your gypsum and calcium chloride additions in half or not adding anything to your water to see if that helps.

 

[dyqik]

First option/question:
Did you use Campden/metabisulphite to remove chloramine? Boston water uses chloramine, and at lower levels, to me it gives an astringent/plastic taste.

If you haven't tasted it before, it's possible that the levels are higher right now for the spring flush that is sometimes done. This time last year I found that even treating with the standard 1/4 tablet per 5 gallons wasn't sufficient to remove all the chloramine in my tap water (I'm on the town system rather than MWRA though).


Second option:
Did you acidify the sparge water? Boston water is low enough in minerals that the sparging process can raise the pH above 6.0 in the mash tun, which allows tannins to be extracted. However, that's far more common and likely with fly sparging than with batch sparging

EDIT: I think I'm wrong on this last question - MWRA water is so low in alkalinity, it should be able to raise the pH of the mash much with batch sparging, unless you do triple batch sparging or something.

 

[kavan]

Thanks for the replies! I've considered going back and brewing without the additions, for sanity alone, but there are characteristics of that I enjoy. I think the mouthfeel is far superior in with the additions. (Plus, I'm a stubborn homebrewer.)

Dyqik -

I've tasted the chloramine before. (tastes like bandaids to me) I don't think that is it. I didn't treat this particular batch, so it is possible that there is some kind of off-flavor combo going on. Boston normally treats their water towards the end of Summer, thats when I need to watch out for chloramine the most.

I didn't acidify the sparge water. I assumed batch sparging wouldn't raise the PH to high enough levels. Could be what I am experiencing.

 

[dyqik]

I've tasted the chloramine before. (tastes like bandaids to me) I don't think that is it. I didn't treat this particular batch, so it is possible that there is some kind of off-flavor combo going on. Boston normally treats their water towards the end of Summer, thats when I need to watch out for chloramine the most.

I didn't acidify the sparge water. I assumed batch sparging wouldn't raise the PH to high enough levels. Could be what I am experiencing.

I think it's worth treating every batch with Campden. I've had both the obvious off-tastes with the traditional band-aid taste, but also milder off-tastes that are harder to pin down at what I think were low levels. That was with treating with 1/4 tablet per 5 gallons, but with a smell of chlorine still remaining after treatment. Sniff the hot liquor tank/strike water - if you smell chlorine when it's heated, it needs more Campden.

With MWRA water the alkalinity is so low that I don't think the pH will rise with batch sparging.