How much malt required to convert rice?

[fluxgame]

Not strictly a brewing question, but loosely related. I'm trying to make some brown rice syrup. As I understand it, brown rice syrup is made by cereal mashing rice along with some amylase enzymes (which they usually get from barley malt). I'm thinking I could just do a mash with a high rice:barley ratio and achieve more or less the same end product. My question is, what ratio do I need? I know rice has no diastatic power on its own, so how much barley do I need to convert a given quantity of rice?

 

[a10t2]

With a modern US 2-row or 6-row, you should be able to mash at least twice the weight of the barley. Ideally you'd check the specs for that particular lot of malt, and that would tell you exactly. The rule of thumb is that you want a weighted average of at least 40 degrees Lintner.

So if, for example, your base malt is 125°Lintner, you could go as low as 40/125 = 32% malt.

 

[fluxgame]

Awesome, thanks for the explanation! So, my current bag of 2-row lists a "Diastatic Power %, Degrees Dry Basis" of 146. I'm assuming this is equivalent to °L, so I can use a rice:barley ratio of about 3.65:1 (27% malt)?

 

[o4_srt]

I'm pretty sure you can buy a-amylase at any hbs, and if not, the web.

 

[fluxgame]

I'm pretty sure you can buy a-amylase at any hbs, and if not, the web.

Obviously this isn't exactly the most practical project, after all you can buy brown rice syrup pretty cheaply in most any grocery store. But, I've got a bunch of brown rice and a bunch of 2-row already laying about. It's more an experiment than anything, I suppose.

 

[a10t2]

Awesome, thanks for the explanation! So, my current bag of 2-row lists a "Diastatic Power %, Degrees Dry Basis" of 146. I'm assuming this is equivalent to °L, so I can use a rice:barley ratio of about 3.65:1 (27% malt)?

Yes, although if you're going that low you'll probably have to mash for a while (maybe a few hours) to get some conversion. Make sure you have some iodine on hand for starch tests.