Adjunct Potential Gravity

I'm looking to use various different starches as adjuncts, I would like to approach this scientifically as possible.
How does one determine the potential gravity of an adjunct, do you mash it with a malt of known potential, then do a calculation based on the weights etc.
Any help in this regard would be appreciated.

I just use a chart like this one
https://www.homebrewtalk.com/wiki/index.php/Adjunct#Grain_Adjuntcts

I meant other non-traditional starches as adjuncts like cassava and sorghum, as I am in Ghana where these are abundant, but malts and other grains has to be imported.

Ah, that makes sense.

If you have a good sense of your system efficiency, maybe you could take a pound of 2-row, mash for an hour and, a pound of the adjunct, mash at normal temps in a gallon of water for an hour, and see what you've got?

So:
Assumption: 2-row Potential Gravity of 1.038
38 * Typical Brewhouse Efficiency = gravity points attributed to 2-row
Total gravity - gravity attributed to 2-row = gravity points attributed to adjunct
Gravity points attributed to adjunct * 1/Typical brewhouse efficiency = Potential gravity of adjunct

If you're getting almost nothing from the adjuncts, you probably need to do a cereal mash

What do you think?

I think the tricky part will be not all starches gelatanize at the same temperature, so trying to measure extract potential yourself doing test mashes will be somewhat confounded by different adjuncts having different starch compositions. To do this well would probably require a pretty serious chemistry lab setup....

You might be able to get a rough idea of extract potential by looking at calories/carbohydrate content from nutritional data. If you assume the extract potential is basically the conversion of all carbohydrates into sugars that might give you a ballpark figure. Similarly, if you can't find carbohydrate info specifically, the calorie content should be pretty close to extract potential after you subtract out calories from fats and proteins.

Anyway, I'd also maybe suggest asking the folks over in the gluten free forum. They're the experts on mashing with non-traditional ingredients.

If you're using something with no diastatic power of its own, you can perform a congress mash and use 1/4 tsp of amylase enzymes (most LHBS carry it) to do the conversion.