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Thread: Mash Conversion trouble when using Rice Flakes

  1. #1
    Join Date
    Jun 2010
    Location
    Cedar Rapids, IA
    Posts
    18

    Mash Conversion trouble when using Rice Flakes

    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.

  2. #2
    Join Date
    Nov 2002
    Location
    Mobile, Alabama, USA
    Posts
    215
    Quote Originally Posted by ChrisEllis View Post
    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.
    What is your degree of attenuation final fermentation? Having any problems there. Something isn't adding up here.

    Can you perform a step mash?

    Maybe check iodine test procedure? Iodine funky or something?
    Todd G Hicks
    BeerDenizen Brewing Services

  3. #3
    Join Date
    Jun 2010
    Location
    Cedar Rapids, IA
    Posts
    18

    Good attenuation

    I am getting good attenuation. Usually around 86% for this brand. My concern is that the last couple of batches had a very slight haze and a bit of a texture that in my mind I attributed to residual starch. That part could all be in my head.

    I can do step mashes, and I do so for many of my beers (I have a Dutch Kuit beer for which I employ a 6-step mash, just to make life difficult for myself). When you brought up step mashes, it got me thinking. I use a mash mixer, so the mash is generally well agitated and doesn't "settle" to easily allow for a sample clean of husks and other such particulate. That could definitely result in false positive for starch. It doesn't explain why I don't have this problem with other beers though. That is, unless the problem is specifically with smaller particles of rice starch that might otherwise have settled out.

    However, I just drew a sample from the fermenter. And while it doesn't look *too* bad, the iodine test is indicative of some amount of residual starch. I used two different tinctures of iodine---one just opened---to rule out some contamination of the iodine.

  4. #4
    Join Date
    Jan 2003
    Location
    Palau
    Posts
    2,077

    Something else...

    2 hours mashing is extreme. I use 20% boiled rice and a 20 minute saccharification rest. That is plenty! Attenuation is down to 1.65P for a very dry beer. You do not require gelatinization of rice flakes. Suggest you calibrate your mash thermometer. Check that your pH is around 5.35. Then look at your iodine test. Don't think you're getting correct information from it. Haze is likely due to other factors like perhaps calcium. Depends on so many factors that I'd leave starch for last. Look at filtration issues too.
    Phillip Kelm--Palau Brewing Company Manager--

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