From looking at the ingredients by fat/sugar/calorie ratios on Trader Joe's products, especially coconut milk, they do dilute their products a lot. I suspect that their soy sauce, now priced in this area at $3/bottle is just half soy sauce watered down by vinegar (news to me too!) and water. I swear I did not notice the vinegar on the ingredients list of Trader Joe's soy sauce until recently. And then, I ran out of it.
Which brings me to wonder if I could recreate the ingredient ratio based on per tablespoon sodium and calories. This is a ratio that I have refilled the TJ bottle with:
1 c Kikoman gluten-free tamari soy sauce (that's right, no wheat)
1/4 c Marukan rice vinegar (at 0 calories and 0 sodium, it's all flavor)
3/4 c filtered water
Shake it all together in the bottle. I have no idea if these liquids separate at all, e.g., if one is heavier than another. Seems to taste ok. A little watered down in appearance; but that's to be expected since wheat (gluten) is really a thickener in soy sauce.
Makes 2 cups.
Let's talk cost comparison.
If you live near a bulk retail store that carries these products, I recommend that you pick up rice vinegar by the gallon (instead of quart or liter) and soy sauce (of a brand you trust, in quart or larger containers).
The Trader Joe's soy sauce bottle suggests that it holds 17.6 fl oz. This is just a pint (2 cups!) plus 1.6 oz.
2 quarts (8 cups) Kikoman tamari soy sauce costs $9.99 (Cash & Carry), $1.25/cup
1 gallon (16 cups) of Marukan rice vinegar costs $7.87 (Cash & Carry), $0.49/cup
1 c soy sauce = 1.25
1/4 c vinegar = 0.12
Total cost = $1.37 per 2 cup batch
Is it worth mixing this myself? Well, I only just picked up the rice vinegar last year because like soy sauce, I use it on a lot of food... from potstickers to salad dressing and as an ingredient for making Asian pickles. Seems worthwhile if the taste is similar.
I'm not sure how this new batch will hold up to other recipes that call for light soy sauce as an ingredient. I'll just have to test.
