how are dark and light soy sauce different

January 25, 2004 4:08 PM

What's the real difference between dark soy sauce and light soy sauce? Fish sauce? If a recipe calls for light (or dark) soy sauce, can one substitute fish sauce? Does fish sauce go bad? Should it be refrigerated, or is it okay to leave it on the shelf for years (which is how long it takes me to use a full bottle)?

Also, if it's not okay to substitute one sauce for another, is there a way to approximate one? For example, our supermarket (in a small town) has an ample supply of food ol' Kikkoman soy sauce, which I assume is dark soy sauce. Is there a way to make it approximate light soy sauce?

I love Asian cooking, but sometimes I'm lost about what I can substitute, and my cookbooks just aren't any help.

posted by jdroth to Food & Drink (16 answers total)

Light soy tends to be saltier and less viscous than dark soy sauce. Unless you're going for an uber authenticity thing, it shouldn't be a problem to substitute the two kinds. However, the fish component in fish sauce gives it quite a different flavor entirely.

BTW i'm not 100% sure but i think kikkoman is light.
posted by juv3nal at 4:20 PM on January 25, 2004

Fish sauce is for Thai cooking.
posted by konolia at 4:21 PM on January 25, 2004

The entry on soy sauce in the Wikipedia and the section on Asian condiments at the invaluable Cook's Thesaurus should answer most of your questions. Essentially:

• Kikkoman is Japanese soy sauce, which is different from Chinese soy sauce. Chinese soy sauce comes in light & dark varieties. Tamari-style soy sauce is the Japanese style that's closest to Chinese soy sauce.
• One can subsitute light soy sauce for fish sauce in a pinch, but a better fascimile can be made using anchovies as well.

I would say that you're probably OK using a tamari-style sauce for most purposes (and anchovies, if you need fish sauce), unless you're an authenticity hound.
posted by Johnny Assay at 4:29 PM on January 25, 2004

Yes, soy sauce should be refrigerated. No, it shouldn't be expected to last years. It won't go bad but over time it will be less tasty and evaporation will ever so slowly make it darker and more concentrated. I don't really cook with fish sauce, disliking the flavor, but I would expect it to be similar in these respects.
posted by majick at 5:27 PM on January 25, 2004

my (limited) experience of cantonese culture suggests that dark/light soy sauce isn't important (personal taste/whatever is in the shop) and that it's not refrigerated (at least in the uk) but that it disappears at an alarming rate.
posted by andrew cooke at 5:41 PM on January 25, 2004

Fish sauce is used in many Asian countries and is made in many different ways. Fish sauce was commonly used in the Roman period and also in England. Someone added tomatoes, a new world food that was more popular in the West, and that is how we got the much maligned Ketchup. Here is a traditional recipe for ketchup

3 cups tomato paste
1/2 cup fish sauce
1/2 cup maple syrup or other sweetner
pepper, garlic

Let ferment for a few days at room temp then consume. It is too bad modern ketchup doesn't use fish sauce which tastes richer and is loaded with vitamins and minerals and protein.
posted by stbalbach at 7:37 PM on January 25, 2004

Kecap manis is Malaysian/Indonesian dark soy sauce. Thick and sweet, has the consistency of molasses. A little goes a long way. Nothing like Kikkoman.

One way to get a little fishy richness into dishes--without seeming too 'weird'--is to use anchovy paste, the kind sold in little squeeze tubes. A teaspoon or two stirred into a pan of spaghetti sauce will give it that "what a great flavor, can't put my finger on it" taste.

If I remember correctly, the Roman fish sauce was called "garum". Salted, fermented fish entrails and such. Mmmmm, boy.
posted by gimonca at 8:16 PM on January 25, 2004

As it turns out, those know-it-alls at PBS have an answer for everything. At least they agree with my anchovy paste idea.
posted by gimonca at 8:18 PM on January 25, 2004

For fish sauce to develop a pleasant, fragrant aroma and taste, the fish must be very fresh. As soon as fishing boats return with their catch, the fish are rinsed and drained, then mixed with sea salt -- two to three parts fish to one part salt by weight. They are then filled into large earthenware jars, lined on the bottom with a layer of salt, and topped with a layer of salt. A woven bamboo mat is placed over the fish and weighted down with heavy rocks to keep the fish from floating when water inside them are extracted out by the salt and fermentation process.

The jars are covered and left in a sunny location for nine months to a year. From time to time, they are uncovered to air out and to let the fish be exposed to direct, hot sunshine, which helps "digest" the fish and turn them into fluid. The periodic "sunning" produces a fish sauce of superior quality, giving it a fragrant aroma and a clear, reddish brown color.

After enough months have passed, the liquid is removed from the jars, preferably through a spigot on the bottom of the jars, so that it passes through the layers of fish remains; or by siphoning. Any sediments are strained out with a clean cloth. The filtered fish sauce is filled into other clean jars and allowed to air out in the sun for a couple of weeks to dissipate the strong fish odors. It is then ready for bottling. The finished product is 100-percent, top-grade, genuine fish sauce.
posted by konolia at 8:30 PM on January 25, 2004

The two big soy sauce brands in the US are Kikkoman and Yamasa. They both have decent websites with explanations of their products and sample recipies. Soy sauce and fish sauce are very different condiments.
posted by gen at 8:56 PM on January 25, 2004

Also, be aware that "lite" soysauce and "light" soysauce are often different. "Lite" being a reference to being lower in sodium.
posted by silusGROK at 10:32 PM on January 25, 2004

There are literally 10 to 20 different kinds (not brands, kinds) of soy sauce on the shelf at my local grocery store (and it's not a big one) here in Korea. I have found that not only does Korean soy sauce tend in general to be quite different from Japanese varieties, it is also important to choose which type of sauce you're going to use, based on what sort of dish it'll be used for. Use cooking-type sauce to dip your sashimi in, for example? No way!

I'm far from a gourmet, and I only know of what I speak from eating well rather than any kind of foofoo mock wine-snobbiness. But once you learn to taste the differences, I think you'll find soys almost as varied and subtle as wine.

Go to an Asian grocery, buy a selection from various countries, and experiment. You won't regret it.
posted by stavrosthewonderchicken at 3:56 AM on January 26, 2004

Fish sauce is very big in Filipino and Thai cooking. (It's called patis in Tagalog and nam-pla in Thai.) The Thai fish sauce I keep in my pantry is a hundred times saltier than soy sauce, and while it makes for good cook'n, either one is a poor substitute for the other in my experience.
posted by brownpau at 8:24 AM on January 26, 2004

I find Japanese tamari to be infinitely superior to Chinese soy sauce. Light or dark, all the Chinese soy sauces I've bought in the West taste like salt and nothing else to me. And fish sauce is so salty that I can never use enough for it to add any flavor.

I use tamari instead of salt in practically everything I cook, Western or Asian, because it gives a heartier flavor that's often missing from vegetarian food. I can almost always find good tamari (or shoyu, which has added wheat) in health food/organic food stores.
posted by fuzz at 10:44 AM on January 26, 2004

fuzz, you took the words right out of my mouth.
posted by Utilitaritron at 12:22 PM on January 26, 2004

Growing up in a Chinese (Cantonese mostly) household, I was taught that light soy sauce is mostly used for flavour, and dark soy sauce is mostly used for colouring. I definitely use more light soy, and save dark for say, giving a bit of a dark colour to fried rice.
posted by Big Fat Tycoon at 6:25 AM on January 27, 2004