I brew a Light American Lager to serve in my brewpub. I consistently have trouble reaching full conversion in the mash... at least so far as my iodine starch tests show. The first 4 batches the grain bill has simply been 50% Pilsner Malt, 17% 6-Row, 33% OIO Toasted Rice Flakes. I use a 50/50 split of RO water and our regular filtered water, then bump up the calcium with some CaCl. I keep my WTG right around 3, so not too thick and not too thin. The mash always takes over 2 hours to reach full conversion. I brewed my 5th batch today with a few tweaks that I had hoped to improve the situation. I cut the 6-row and replaced that with more Pils malt (that tweak was just for taste), and I cut half of the rice flakes to be replaced with rice syrup solids in the boil. I even added a lower conversion temperature rest with an addition of Amylo 300 amyloglucosidase. However, 2 hours in, with half the amount of rice in the mash and a healthy addition of Amylo 300, my iodine starch tests is showing up incomplete. Wha?
I have not been doing a cereal mash or a gelatinization step, as I understand the flaked rice to be pre-gelatinized. Is this incorrect information?
Is anybody aware of any peculiarities to OIO Toasted Flaked Rice, or rice flakes in general, that might result in false negatives on iodine starch tests? Or can you think of any other issues that I might be overlooking? I don't have conversion issues with any other beer that I brew. This one just has me scratching my head. The only other thing that I can think of is that there's some problem with my RO filter, the piping for it, or the RO reserve tank, as this is the only beer in which I have been using RO water. I tasted the water prior to the brew though, and nothing tasted off.
I have not been doing a cereal mash or a gelatinization step, as I understand the flaked rice to be pre-gelatinized. Is this incorrect information?
Is anybody aware of any peculiarities to OIO Toasted Flaked Rice, or rice flakes in general, that might result in false negatives on iodine starch tests? Or can you think of any other issues that I might be overlooking? I don't have conversion issues with any other beer that I brew. This one just has me scratching my head. The only other thing that I can think of is that there's some problem with my RO filter, the piping for it, or the RO reserve tank, as this is the only beer in which I have been using RO water. I tasted the water prior to the brew though, and nothing tasted off.
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