Author Topic: Sweet Potato Mashing and Starch Conversion  (Read 3044 times)

Offline cowboygun

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Sweet Potato Mashing and Starch Conversion
« on: October 07, 2016, 02:32:44 AM »
Hi every one,

I am going to make a sweet potato beer and I am looking for more information. I found some good info here:

http://byo.com/bock/item/323-brewing-with-potatoes-techniques
http://www.jbc.org/content/44/1/19.full.pdf
https://www.reddit.com/r/Homebrewing/comments/1cvbo0/no_grain_sweet_potato_beer_test_1/
https://www.youtube.com/watch?v=1PSvCRtVdZU

First off i am using 25.5 lbs of unprocessed sweet potatoes. Now I have seen that boiling the potatoes to release the starches a lot. If the potatoes were run through a food processor would the boil still be required? My concern is the denaturing of the enzymes that naturally occur in the potato. I am also using 6-row and Maris Otter at 3 lbs each with 1.5 lbs of crystal 120 and 1.5 lbs of rice hulls I am considering getting more Rice hulls as 25 lbs of sweet potatoes is roughly 5 plastic grocery bags of potatoes and a stuck mash worries me.

BYO points out, "Potato starch gelatinizes at relatively low temperatures, around 130 °F (54 °C) for most mealy varieties. As such, the starch is accessible to the saccharification enzymes at typical mash temperatures — 148–158 °F (64–70 °C)." Even after this is stated, a couple of times, boiling the sweet potato is mentioned. So I am concerned and curious as to what is recommended and also any thoughts on roasting the sweet potato after being run through the food processor?

If i do a rest at 130F would there be a need to boil before a full mash? I do not want to lose the enzymatic activity. I was considering mashing in at 152-153F. To pull available starches out of the sweet potato and still keep potato flavor what would need to happen if anything? Any help would be appreciated.

simple cider in secondary

Offline brewfun

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Re: Sweet Potato Mashing and Starch Conversion
« Reply #1 on: October 08, 2016, 08:02:29 AM »
Personally, I'd skip all the rests and just gelatinize the sweet potato starch.  I'd then press the potato through a ricer, and then again in cheesecloth with weight to exrtact as much of the starchy water as possible. That water would then be the the mash water for the bit of grain you have. The enzymes in barley are stronger than those in the potato.
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