A few years ago I decided to try to figure out how to make brown rice syrup. I didn't find a whole lot of information to go on, but I went with what little information I had and did some experimenting. The result was a syrup of the right consistency but muddy looking (kind of like beef gravy) rather than translucent. Worse than that, while it had a degree of sweetness to it, it also had an unbearably bitter aftertaste. So bad that when I finished the experiment I never wanted to see brown rice syrup again nor even a single grain of brown rice. Bleck!
The problem was probably one of three things: either some of the starches hadn't converted to sugar, or I used too much barley which itself may have been bitter, or I let the barley sprout for too long and that caused it to be bitter.
These seem to be the three most important variables: how long to sprout the barley, how much barley to use, and how long to heat the mixture in order to get all the starches to convert.
The basic process, I believe, is this. You sprout some barley. The sprouting process releases enzymes in the barley, which is what will digest the starches in the rice, turning them into sugars. You cook the rice, then cool it to a temperature below which the enzymes won't be destroyed. (I've seen conflicting information on just what that temperature is, but 140 degrees Fahrenheit works.) Once cooled you add the sprouted barley (crushed, or chopped in a food processor) and then let the enzymes go to work. You have to keep the mixture heated to the 140 degree range the whole time (the oven on its lowest setting is the best bet for me) and it will take many hours. Once you've let it digest long enough strain off the liquid through several layers of cheesecloth and boil the resulting liquid down to the desired consistency.
The first time I experimented I tried to control for the amount of barley used. I divided the cooked rice into four different containers. At that point I didn't know whether I should leave the barley whole or chop it up. I thought chopping might help, but I also worried that it might damage the enzymes somehow (shows how clueless I was). So in one bowl I put a tablespoon of whole barley, in another bowl a tablespoon of chopped barley, in a third bowl I put a quarter cup of whole barley and in a fourth bowl I put a quarter cup of chopped barley. Within five minutes, the two bowls with the chopped barley were bubbly, just like when you proof yeast, so I knew that chopping the barley was beneficial. The other bowls followed along shortly thereafter, but at a slower pace. As the enzymes continued their work, the mixtures began to thin considerably. I could tell that the starches were breaking down. The bowl with a quarter cup of chopped barley did the best, so it would seem that more barley is better (sounds logical). However, I don't know if the barley is contributing to the bitter taste, so it might be the case that more is not actually better. It might be faster, but not better.
This week I decided to take another stab at it. Since the last time I experimented I'd come across a recipe in a 1975 issue of Mother Earth News magazine for what they called "Grain Honey" . It sounded similar to everything I'd tried and so I hoped that they had all the kinks ironed out for me, as to amounts and timing and all of that. The only thing I did differently was to use four tablespoons of sprouted barley instead of three. That was because my sprouts were only two days old and I was afraid they wouldn't be potent enough. So after hours of baking, then boiling it all down, I had another syrup of the perfect consistency. It was not quite translucent but at least it didn't look like beef gravy this time. I took a lick. Definitely far sweeter than the last batch...getting close...but wait, ugh, there it was again--that horrendous aftertaste!
So, it's back to the drawing board. Did that one extra tablespoon of barley ruin it? Or did the starches not completely convert? It's frustrating with all these variables to manipulate--the ratio of rice to barley, the time you let the barley sprout, and how long to let the rice cook.
I suspect there's another variable. When I experimented the first time, I chopped my rice in a coffee grinder and made it into a flour of sorts. I figured that the finer it was, the more effectively the enzymes could go to work on it. The Grain Honey recipe leaves the rice whole. So using the Grain Honey recipe, when the rice was done cooking with the barley I had rice in a watery fluid. I put that all in a cheesecloth-lined strainer and squeezed the liquid through. But afterwards I thought, if there are still rice kernels left behind, aren't those kernels still unconverted starches? And as I squeezed, wasn't I maybe squeezing out starch as well as sugar?
It seems that ideally you'd want to convert it all. Using the Grain Honey recipe I ended up with only about 2 fluid ounces of brown rice syrup. If that's all you get, then it would be totally uneconomical to make this at home. The store-bought stuff is cheaper. Yet, I was left with a massive glob of sticky rice. There has to be a way to get it all to convert.
So, it's back to the drawing board yet again. This time I think I'll try the Mother Earth News recipe again, but I'll grind the rice before I cook it, and let it cook much longer.
There are some other possible variables that I'll look into after I try this, but if this works then Hooray! I'll let you know.
[See my follow-up post The Homemade Brown Rice Syrup Blues, Part 2.]