In Nobu’s Vegetarian Cookbook, Matsuhisa-sama makes tomato salt and yuzu salt by combining 3.5 oz (100g) of rock salt and 1/2 cup (100 ml) of the appropriate juice and then drying out the mixture in an oven for 2-3 days. But the soy salt used in his book has no recipe for the ingredient. Nobu’s Vegetarian Cookbook describes the soy salt as a mixture of soy, salt and starch (see the glossary entry on p. 173). I believe this is the product Matsuhisa-sama may be referring to: http://www.nymtc.com/pl_mtcpremium/200709soysalt.html and it appears to be also available here: http://www.atthemeadow.com/shop/index.php?main_page=product_info&products_id=340
Still, I thought I’d try and use the tomato/yuzu salt recipe as a template to make the soy salt. Since this was an experiment, I thought I’d make a half batch.
So I weighed out 50g of Diamond Crystal Kosher Salt (thank you Chef Thomas Keller) and 50ml of
Kikkoman Soy Sauce. I mixed it together in a measuring cup and was pleasantly surprised to sea that
the salt didn’t complete dissolve into the soy sauce. So I lined a baking pan with non-stick aluminum foil and then topped it with a parchment sheet. Onto the parchment sheet, I spread the soy/salt
mixture as evenly as I could and placed it into my countertop oven. The oven. I set to ‘warm’ since that was the lowest setting to let the mixture ‘dry out’.
As it so happened, it took 30 minutes plus another 15 to ‘sufficiently’ dry out the mixture in my
countertop oven (rather than the proposed/expected 2-3 days). Once it was done, I did my best to get the dried out mixture off the parchment paper and to get it ready for the food processor.
The following morning, I decided to try it on the tamago-yaki my wife made for breakfast as a ‘finishing salt’. The soy salt I made definitely added that sparkle of flavor – not unlike the experience that Chef Thomas Keller describes when, “…you bite down on a crystal of it on foie gras, for example, it’s amazing – it just explodes with flavor” (The French Laundry Cookbook, p.181).
Truth be told – I’m not sure how what I made compares to the Kamebishi product, since it contains soy sauce, potato starch and dextrin (essentially dehydrated soy sauce). I’ve got to imagine that mine has to be saltier since there’s no starch and added salt. At some point, I’m going to need to get a small batch of the Kamebishi soy salt and do a side-by-side taste comparison. But for now, my wife and I are pretty happy with what I made. As I understand it, Matsuhisa-sama currently uses the soy salt for tempura items, sashimi and the umami sea bass (I’d imagine that’s the vegetable or dashi marinated sea bass: http://hongkong-ic.intercontinental.com/pdf/nobu/nobu_umami_%20201205_1920.pdf).