What are the negative effects of using old malts in all-grain brewing?

[Silver_Is_Money]

What typical flavor defects are noted for the case of brewing with grains that may be several years old?

 

[Dcpcooks]

I’d suspect dull flavor, maybe some rancid flavors from the fat turning rancid.

You should be able to taste rancid and stale with a few bites of grain.

 

[snowtiger1987]

If the grain smells and/or tastes stale so will the beer.

 

[MaxStout]

Loss of flavor, and likely oxidation effects. To what degree depends on how the grain has been stored and/or if crushed. Uncrushed, sealed in an airtight container and in a cool place would minimize the degradation. If the grain has been stored in a bag, or worse yet, crushed, it may not be very good at all.

 

[Silver_Is_Money]

All good advice above. Thanks!!!

What can you report were the oldest grains you have used and still made a fine beer?

 

[user 125772]

old grain loses it's diastic power as well, so you may end up with starch water, instead of wort.

 

[RPh_Guy]

I'll tell you what... crushed grain that sits around for a couple months at room temperature makes really awful beer -- lacking any decent flavor and dominated by stale and almost metallic taste.
Gross. Lesson learned the hard way.

 

[SoCal-Doug]

Defects? No reason to get technical or beat around the bush on this... Your brew could taste like $hit.

 

[Silver_Is_Money]

How long can uncrushed grains last and still make good beer?

 

[PADave]

How long can uncrushed grains last and still make good beer?

Can't really answer that question, too many factors involved. You are safe for a year, probably two. BUT that depends on how they are stored. How old were they before you bought them? Grains and hops are a plant crop, they only get harvested once a year. Not like there is a continuous supply of them being made. Best thing to do is taste the grain for yourself before using it.

 

[balrog]

I buy crushed.
Stored in bags in cool dark basement until use.
I try to brew within a week or two of receipt but Life can interfere. Silly Life.
Three months was the longest. It was fine but a little dull. Hard to really tell because (a) never made it before or since so nothing to compare; and (b) it was a darker amber brew and not a lighter brew that would show issues better.
I've made plenty that were 40-50days from purchase and they are fine.
One man's opinion.
YMMV
QED
etc.