Off flavors from old or poorly crushed grain?

[HOPCousin]

I have had a flavor pop up several times which tastes minerally and kind of harsh. I've tracked is that when I get my grain from my friends LHBS or when I've had to order by mail in the past this flavor hasn't been present when looking back at my brew journal. I looked in my homebrew books and was reading about tannins from a poor crush that may be contributing? Also old grain came up several times in the reading when looking for this off flavor.

Has anyone else run into this?

 

[kylevester]

I've not heard of off flavors from tannins due to a poor crush, where did you hear that?

Sparging with too hot of water will pull harshness from tannins out and you will get more harshness/roastiness from dark grains if you mash them for the full saccharification rest.

I'm not understanding where you think the problem is. Is it the LHBS grain or the mail order grain or some other source that you get the problems?

Old grain can definitely give off flavors, especially if it's crushed, due to oxidation of the grains. Fresher is better, however grains keep well so long they're treated well.

 

[HOPCousin]

I noticed that I only run into this off flavor from grain purchased at my LHBS. It's a dry mineral like taste that lacks freshness or sweetness even after 5 weeks of aging in the keg.

It was a malty IPA with a mash temp of 152. I did a batch sparge with 170 degree water. I use beer smith for my profiles.

I used WLP007 with a fermentation temp that got up to 74 at peak.

I found the info in Gordon Strong's book. I'm mainly looking to see if anyone has run into a similar off flavor and if they traced it to the same origin.

 

[BenS]

Whenever I have used old malt, I have noticed horrible efficiency.