Unmalted Gluten-Free Brew Day Fail: Questions

[kdw2pd]

Hi all,

Following advice I received and further forum reading, I took my first whack at a 5 gallon GF brew day. Following the method that Legume has laid out, I did the following:
1.) Crushed 11.5lb of bird seed (primarily millet, some milo/corn) in corona mill.
2.) Heated ~6 gallons of RO water (pH adjusted ~5.5) to 180F, stirred in grains and added 15ml of Termamyl. I recirculated in a BIAB setup for 75 minutes.
3.) Added some ice and 1 gallon of water, dropped temp to 140F, added 15ml of AMG-300L and ~2.5lbs of GF rolled oats. After 90 minutes, the wort was still grey, sticky, and starchy, and was at 1.035, when at 60% efficiency, it should have been 1.052. After another hour, there was no further conversion. I ended up dumping the wort, as it was still super starchy.

I really want to get this right, so I have a couple questions.

1.) Is 75 minutes at 180F enough for gelatinization? Would it be easier to just cereal-mash the grains and boil for a half hour or so? Is 15ml enough Termamyl?
2.) Are the Termamyl and AMG-300L that pH sensitive? Termamyl can work at the upper ends of usual mash range (pH 5.5), but AMG-300 needs to be 3.5 - 4. When I drop the temp to 140F to add the AMG, do I need to drop the pH for conversion, then add something basic to bring the pH back up after the mash to get it into regular beer pH range?
3.) Is 140F the right temp for AMG-300? Is 15ml enough?

 

[Legume]

Hi all,

Following advice I received and further forum reading, I took my first whack at a 5 gallon GF brew day. Following the method that Legume has laid out, I did the following:
1.) Crushed 11.5lb of bird seed (primarily millet, some milo/corn) in corona mill.
2.) Heated ~6 gallons of RO water (pH adjusted ~5.5) to 180F, stirred in grains and added 15ml of Termamyl. I recirculated in a BIAB setup for 75 minutes.
3.) Added some ice and 1 gallon of water, dropped temp to 140F, added 15ml of AMG-300L and ~2.5lbs of GF rolled oats. After 90 minutes, the wort was still grey, sticky, and starchy, and was at 1.035, when at 60% efficiency, it should have been 1.052. After another hour, there was no further conversion. I ended up dumping the wort, as it was still super starchy.

I really want to get this right, so I have a couple questions.

1.) Is 75 minutes at 180F enough for gelatinization? Would it be easier to just cereal-mash the grains and boil for a half hour or so? Is 15ml enough Termamyl?

You added your (cold) grain to 180 F water...so your mash temp was lower than 180 F.
I mash in my brew pot and (direct) heat the whole mess to 180 (stiring the whole time the burner is on). I have never experimented to see how little termamyl i can get away with, 15ml may be enough; but i normally use about twice that ammount. Another watch out is the crush, i grind GF grains very fine (i run them through the mill twice). When i have been lazy and milled only once (resulting in a coarser grind), my efficiency has suffered a lot. You want to see a lot of flour in the crushed grain...i have actually been thinking of just buying millet flour and using it for 1/3 of my grain bill (have not had a chance to test this yet).

If you are curious about your efficency at the end of the 180 F rest, you can measure BRIX at this point. The BRIX does not change much between the end of the 180 F rest and the end of the 140F rest.

2.) Are the Termamyl and AMG-300L that pH sensitive? Termamyl can work at the upper ends of usual mash range (pH 5.5), but AMG-300 needs to be 3.5 - 4. When I drop the temp to 140F to add the AMG, do I need to drop the pH for conversion, then add something basic to bring the pH back up after the mash to get it into regular beer pH range?

I dont think they are all that pH sensitive.
I dont test my pH any more, i just add 1 tsp CaCl and .5 to 2 tsp gypsum to the RO water in my mash.


3.) Is 140F the right temp for AMG-300? Is 15ml enough?

Yes, yes.

My guess is that the low efficiency is due to a coarse grind combined with a slightly low gel rest temp (didnt hit 180 F). Also lots of stiring and agitation during the 180F rest increases efficiency.

The wort should be cloudy (and probably starch positive, i dont test it) at sparging. All of the suspended stuff will drop out during the boil and in the primary fermentor. Try to work on the efficiency, but dont worry about starchy wort.

 

[kdw2pd]

Thanks for the quick reply and good feedback, Legume! I'll follow your advice and give it another shot.

One other question: using GF grains that have already been gelatinized (GF oats, minute rice), should I still add them during the 190F Termamyl rest, or stir them in at 140F with the AMG-300?

 

[Legume]

You should still add the pre gelatinized grains to the 180 F rest, as this is the only step with alpha amylase activity.

If added to the 140F rest where only beta amylse is active, they will not contribute much to the gravity; but will contribute a lot of starch to your wort.

 

[fofusak]

Did you taste your wort? Maybe the starch positives were just things floating around. (you'll never get rid of those)

I had a similar failure, sadly my wort wasn't sweet at all and I dumped it down the drain.

 

[KeinGluten]

I haven't read the original post in a while, so I don't know if the 180°F strike temperature accounts for this, but if you mix that 11.5lbs of grain into 6 gallons of 180°F water, the temperature of the resultant mixture will only be 170°F. Could this have caused incomplete gelatinization? I bring my mash to a boil, so I can't really add experience of my own as far as gelatinization goes.

If you want the grain/water mixture to be 180°F, the strike water needs to be 191°F, according to the mash infusion/strike water calculator on brewersfriend.