To my understanding the starches in potatoes need to be gelated before they can be converted into simple sugars. This process is done through boiling, my concern is that I will loose valuable sugars into the boiling pot from this process before I add amylase enzyme into the mash. A possible solution I have come up with is, the pot that I boil in would be the same pot that I add my enzyme into after the water has cooled to a proper temperature. Can anyone foresee problems that would arise from this process, or have thoughts on a different route to achieve a good conversion?

3 Answers 3


Starch is stored as tightly packed granules of amylose and amylopectin, both long polymers (chains) of sugars. At room temperature only a small portion of the granules will become hydrated in water and so most of the sugar content will be inaccessible to enzymes that split the simple sugars off the amylose and amylopectin chains. Gelation is the loosening of the packed polymers and occurs at varying temperatures for various plants and seeds. Harold McGee's text "On Food and Cooking" give the gelation temp range of potato starch as 136-150 F (58-65 C). Neither raising the temperature to gelation range, nor boiling will reduce the sugar content of any starch, since the glycosidic (C-O-C) bonds are too strong for that to occur. What might happen however is that higher temperatures may denature the hydrolytic enzymes and reduce the natural ability to split off simple sugars from the chained together polymeric starch.

So you might not need to initially raise the temp to boiling starch unless you are doing so to prevent bacterial growth. You could conceivably have a mashing period and then raise the temp to sterilization temps.




You will not lose sugar to the boil water, but it will lose starch, and yes you can use the same water you boil the potatoes in to add the enzyme after it cools.

The loss of starch to the water will be minimal and would not worry about it if you change the water out after boiling.

To help conversion, mashing the potatoes and making mashed potato will help the enzyme reach the starches. and using a brew bag will help you take remove potato chunks out of it.

in the end to make it simple, boil potatoes and make mashed potato, use BIAB and convert starches to sugars, remove and follow the rest of your procedure to ferment.


Roast/bake the potatoes. No losses of starch (potential sugar) to the water. I make a sweet potato amber ale and that's how I process/break down the potatoes.

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