Cereal mash today, brew tomorrow?

[gmac]

I was gonna brew today but my wife had other ideas.
So, in order to save time tomorrow, I was wondering if I could do a cereal mash today (4 lbs corn meal, 2 lbs 2-row) and then brew tomorrow.  Since everything gets boiled at the end of the process.  Is there a problem if I cover this well and put it in the fridge until tomorrow?  Then, I would add this to 12 lbs of pilsner malt and mash.

I know 6 row would be better but I don't have any so I'm winging it with pilsner.  Is there enough enzyme in the 2:1 ratio to convert the corn properly?  Palmer says not to exceed 4:1 but doesn't say what base malt that ratio is best with.  I figured 2:1 can't hurt.

[denny]

You'll be fine with the pils malt.  As to doing it a day ahead, I want to say "sure" but see what others have to say.

[eltharyon]

My only worry is the enzymes will keep working on the corn, maybe breaking off more glucose.

[denny]

My only worry is the enzymes will keep working on the corn, maybe breaking off more glucose.

But he'll be boiling the cereal mash, which should shut down the enzymes.

[hopfenundmalz]

You might want to heat up the cereal mash if you have it in the frige overnight, or compensate with you strike water temp.

[gmac]

And sterilize everything after a 15 minute boil.  I was gonna tightly cover the stock pot with Saran wrap to reduce contamination in the fridge so I think I'll go ahead and give it a try.  I do want to hear if anyone else has done this with success or disasterous results though.

[denny]

The closest thing I've done is to do the minimash for my partial mash cream ale the day before, then refrigerate the wort from it overnight.  It's always worked fine for me.

[gmac]

You might want to heat up the cereal mash if you have it in the frige overnight, or compensate with you strike water temp.

I was actually thinking of adding it to the strike water as I was heating it and then add it and the strike water to the mash tun and then mash in the remaining malt as usual.  Would make a real thin gruel in 40L of water but I can't see how it would matter.  Then I'd adjust my strike temp for the remaining grain as per usual.

[jeffy]

Instead of putting it into the fridge, why not put it into the oven at its lowest setting?  You can likely keep it at about 150 overnight and avoid the problems of heating it the next day.  AND you'll be sure that conversion has finished!

[eltharyon]

My only worry is the enzymes will keep working on the corn, maybe breaking off more glucose.

But he'll be boiling the cereal mash, which should shut down the enzymes.

Good Point Denny I wasn't even thinking about that part.

[gmac]

Instead of putting it into the fridge, why not put it into the oven at its lowest setting?  You can likely keep it at about 150 overnight and avoid the problems of heating it the next day.  AND you'll be sure that conversion has finished!

But after boiling, wouldn't it be essentially inert?
But, you make we wonder, what would happen if I just put the water, malt and corn together and put them in the oven overnight at 150 without bothering to boil.  Nothing's probably gonna grow at that temp (bacteria) and it would certainly be converted after a 10 hour rest (I like my sleep).  Since this is an adjunct, I think you really want as much conversion as possible anyway.  I don't expect any body to come from the corn, just fermentables and a bit of corn flavour.

[denny]

I _think_ you need the boiling to gelatinize the starches.  Although with corn, that may very well happen at mash temps.

[gmac]

Yeah, Palmer says 165 to 170 for corn to gelatinize.
I'll go old-school this time.
What I described above would probably work if you boiled the corn meal, then added the grain and did the overnight bake at 150 but I know you want to add the malt to prevent it from becoming a lump of sticky corn meal. 

[gmac]

Done.  Still not sure if I did this right.
Added 2 lbs pilsner and 3.5 lbs corn meal (was gonna use 4 lbs but this was what I already had open).
Added 11 L water.
Brought to 145 and let sit for 15 mins covered - may have overshot this temp somewhat.  Hard to gauge proper temp in the entire body of the mash.
Brought to a boil and boiled for 15 mins.
Cooling now.

Palmer talks about bringing it to the conversion rest at 155 but then goes on to say that corn needs 165 to 172 to convert but that's awfully close to mash-out temps and I was going to try to stop at 170 but shot past so I said "screw it" and went for the boil.  Unless I'm really missing something, the purpose behind a cereal mash is to make the starch available for conversion in the main mash, not to convert the starch in the cereal mash so I can't really decide if this second rest matters or not since it's gonna be in with the main mash later.  I would think that in many ways, a handful of corn starch added directly to the main mash would accomplish the same from a gravity standpoint although it wouldn't add the flavour that I'm after and might make sparging a nightmare.

I'll let you know how the brew goes and if this worked or not.

[gmac]

I brewed the beer, it came out way higher in gravity than I anticipated and I watered it down.  Only comment, super slow sparging.  If I ever do this again, I'm gonna add rice hulls because it took hours.  I didn't have any but I won't do it again without them.
10 gals is bubbling away merrily in a swamp cooler.  We'll see how it turns out.
Thanks