On Nov. 28, I wrapped eight lumps of raw barley dough in fig leaves and put them in loosely lidded plastic containers. Forty days later, I mixed the now-rotted barley with flour, salt and water and set the result in a warm spot to rot for two months more. Then I ate some.
I was just following the medieval Arab recipes for a sauce called murri. Really. Rot some barley, then rot it some more; that's what they tell you to do. You could also mix the rotted barley with milk instead of water and make a sort of relish called ka^makh.
I'd made my first batch of rotted barley about 10 years earlier. At the time, I asked a medical researcher whether there might be anything dangerous in these rotted barley condiments, and he warned me that they were probably infected with the common mold Aspergillus flavus, which produces dangerous carcinogens called aflatoxins. So after tasting the result of that first experiment, I washed my mouth out about 70 times.
The sauce I got at the time was pleasant but not exactly exciting. It didn't seem so attractive that I could imagine cooks going to all the trouble to make it, much less overlooking the rather ghastly process by which it's made. I wasn't at all sure I'd got it right.
So last year I decided to try another batch of murri. This time, I sent the results of my rotting to a laboratory to find out whether there was indeed anything dangerous in it (see "OK, It's Rotted . . .," below).
Regular Food section readers have already met my eight lumps of barley dough, which I was rotting in three batches according to the slightly contradictory recipes I'd found in medieval manuscripts. We did the first stage of rotting in the Times Test Kitchen--very far from the food preparation area, you may be sure.
The first of the three batches consisted of five lumps of dough crowded in a single box. In these rather moist conditions, the barley rotted vigorously. After three days, the lumps had greenish spots and were covered with a cloud of translucent threads, indicating that molds of the genus aspergillus had taken up living quarters. We nicknamed these lumps Spot, Whiskers, Einstein, Skinhead and Johnny Rotten, and after 40 days they were mottled all over in black, white, charcoal and about four shades of green.
The second batch was rotted in drier circumstances, only two lumps to the box. Kate Moss and Captain Picard, as we called them, developed a greenish tinge and a few tiny white patches but no cloud of threads.
Finally, one lump was rotted under ashes, as a 10th century recipe suggests. This guy, Pig Pen, also rotted only slightly.
After 40 days, I ground the lumps up and made each batch into a paste with flour, water and salt. The recipes say to rot the paste on your rooftop in the middle of summer, so I put the three batches on a heating pad on the low setting, which kept the mixtures at about 95 degrees. I stirred and moistened them all daily for 40 days. Finally, I added more water and waited another 10 days before extracting a liquid sauce.
Here's what we got.
Kate Moss, Captain Picard and Pig Pen turned pinkish tan (Pig Pen with an ash-gray tinge). The unappealing "liquid" sauce I got from those batches was like salty glue with a sickly-sweet aroma. By contrast, the totally rotten batch (Spot, Whiskers et al.), which started out green, quickly turned a deep mahogany brown. At first it smelled like rotting leaves or a damp basement, but within 10 days it smelled distinctly like . . .
Yes, soy sauce. The sauce extracted from it had a comparatively earthy (some said muddy) texture and flavor, but there was no doubt about it: Murri was a medieval Mediterranean soy sauce.
Big surprise; I had always assumed that soy sauce had to be made from beans. But the usual Japanese soy sauce recipe is 50% wheat, and it turns out that oats, millet, rye and even barley are sometimes added in China and Korea. In fact, there's no reason you have to use any beans at all. All you need is proteins and carbohydrates, which are also found in grain.
The process is basically the same whether you're making soy sauce or murri. In the first stage, the moist dough or soybeans become infected with molds, which can grow where conditions are too dry for yeasts or bacteria. The molds break down starches to sugars and proteins to amino acids.
In the next stage, water and salt are added. Now yeasts and bacteria take over--not just any yeasts and bacteria, of course, only those that can live in a fairly salty environment (soy sauce is 18% salt; the murri paste is 25% salt by weight before water is added).
At this point, a lot of chemical reactions start. Some carbohydrates are turned into acids, including glutamic acid, which is related to MSG. The yeasts produce alcohol; it combines with the various acids to make the aromatic compounds called esters. The result is the sweet, appetizing soy sauce flavor. The longer it ages, the stronger the flavor.