Flaked corn off-flavors

My first two all grain batches were awful!! They tasted grainy and like cardboard. That was two yeas ago. I attributed them to the crappy city water and have been using bottled water and a ph stabilizer ever since with no problems. I also have not used flaked corn since those first batches. Last month I brewed a lager with flaked corn and now it has the same taste!!
Is there something that I need to do different with the corn before or during the mash? I do a simple batch sparge with a protein rest at the beginning. Any help would be greatly appreciated.

Maybe you just don't like the flavor?

the cardboard flavor is oxidation. you are aerating someplace your not supposed to.

To be clear, your flaked corn wouldn;t happen to be frosted would it?

No it's not frosted

Good. Assaid, the cardboard indicates oxidation. Likely entrained post boil at some point in your process. But, "maybe" a stretch could have some to do with the age of the flakes too. Just cause you had them a week doesn't mean they couldn' be years old. In fact, I don' buy adjuncts from my LHBS because they sit forever.

Maybe next time give it a go with Organic cereal flakes from a health food store. If the flavor re-occurs it may have something to do with your process and that the beer is so subtle it shows through where it otherwise wouldn't.

I assume this is a American lager? Thoise can be a b1tch to brew as they highlight everything that one can or could do without 100% precision.

Could the grainy flavor be caused by improper grain milling?

Could the flaked corn taste be DMS?

Sounds like oxidation and tannins extracted from the husks.

Try a really simple recipe (preferably one that's tried and true that others her report success with).

Don't splash the wort while it's hot. Don't splash the beer while it's fermenting or after it's fermented. Don't oversparge.

Can you isolate anything in your process where you might have done any of the above?

@Meddin - OP wasn't talking about a corn flavour but wondering if the cardboard flavour could be attibuted to the use of flaked corn.

I don't splash anything or anytime. It's strange. I have brewed over 30 batches w/ no problems. I batch sparge, so I don't see how I could over spage. I'll just try it again and try to narrow down the problem.

DMS is di-methyl sulfide. Grain contains a precursor to it (ssm from memory) which is part of the reason to have a roiling boil, uncovered for an hour or so. It reveals itself as a cooked cabbage/creamed corn/vegetal flavour in the final beer.

If you outline your process from mash to bottle/keg it might help to at least eliminate some possiblilities.

manticle said:

DMS is di-methyl sulfide. Grain contains a precursor to it (ssm from memory) which is part of the reason to have a roiling boil, uncovered for an hour or so.

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and you can smell it during the boil, I hate the smell, but never appeared in the smell or taste of the final product. One of the few issues I have not yet had.

Wellshooter said:

and you can smell it during the boil, I hate the smell, but never appeared in the smell or taste of the final product. One of the few issues I have not yet had.

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I've sometimes smelt it while the wort is chilling and it smells like rotting cabbage to me. Luckily enough none in the beers I've made either.

manticle said:

DMS is di-methyl sulfide. Grain contains a precursor to it (ssm from memory) which is part of the reason to have a roiling boil, uncovered for an hour or so. It reveals itself as a cooked cabbage/creamed corn/vegetal flavour in the final beer.

If you outline your process from mash to bottle/keg it might help to at least eliminate some possiblilities.

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8# 2 row
1# flaked corn
.5# honey malt

1hr @ 151* w/ 3.8gal H2O
drained and batch sparged w/ 4gal @ 170*

1hr boil
1oz saaz 60 min
1/2oz saaz 30 min
1/2oz saaz at knockout

aerate w/ a stone

2 pkg. european lager yeast

10 days @ 50*
1 day @ 65*
still lagering @ 32.5* for two weeks now

I use a coleman 48qt. cooler w/ a cpvc pipe manifold


This is the same procedure that I have used before(not with this recipe) with no problem. When I drained the first time there was air in the manifold during the recirculation, but I don't think that would cause the problem.

The corn flavor usually goes away if you age it.

chefkdub said:

8# 2 row



This is the same procedure that I have used before(not with this recipe) with no problem. When I drained the first time there was air in the manifold during the recirculation, but I don't think that would cause the problem.

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And when you drain it's done gently through a hose or similar? Minimise splashing etc? How cold is the brew before it goes into the fermenter?

Besides this, what about when you are fermenting? Is there any likelihood the beer would be getting agitated after primary has commenced?

If the flavours are due to oxidation it's probably something in the processes between fermenter and final vessel rather than hot side aeration (which some brewers dispiute being a problem on a homebrew scale). Cardboard is the most commonly described oxidation flavour.

Are you kegging or bottling? How are you transferring to the keg or bottle?

If I read your post correctly, it seems as if you are tasting this while the beer is still fermenting. At what point? While I wouldn't describe it as anything like cardboard, lagers produce a lot of sulphur while fermenting and beer can generally taste and smell very odd while it's doing its thing. Could it simply be a byproduct of fermentation that will dissipate but your memory of your very first AG brews are still with you suggesting the same flavour?

A good AG brew (or any type) shouldn't taste like cardboard. I haven't used flaked corn but it seems odd that an adjunct would result in oxidative flavours.

Primary was in a brew bucket and then siphoned into a keg with an air lock.
When I sparge there is no splashing.
It was 55* when it went into the primary.
I'm starting to think that it my be caused by old flaked corn. Is that a possibility?

I can't help you there.

Doesn't sound like you're splashing. Try the recipe without the flaked corn (could try rice or polenta if you want to use a lightening adjunct) and see how that comes out.

manticle said:

I can't help you there.

Doesn't sound like you're splashing. Try the recipe without the flaked corn (could try rice or polenta if you want to use a lightening adjunct) and see how that comes out.

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Do need to boil the polenta before adding it to the mash or do you just throw it in?

chefkdub said:

Do need to boil the polenta before adding it to the mash or do you just throw it in?

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Not something I use. There are regular polenta users on the other homebrewing forum I frequent. Heres a relevant thread: http://www.aussiehomebrewer.com/forum/index.php?showtopic=39633

Main suggestions seem to be that while you might theoretically be able to add it straight to the mash, you will get better results cooking it first.

Thirsty-boy and MHB are two posters on there who know their stuff particularly well although most people discussing have a pretty good grasp on things.

Rice definitely needs to be cooked first.