Generally, in any Asian house hold, soy sauce is the ultimate umami agent in the kitchen. It is used as a dipping sauce, based for stir fry, acts as an ingredient for soups and simply poured over rice as a seasoning. How do you know exactly which one to use and for what?
Well, like the world - there will be no evil if there was no good, one with out the other - will not exist. OK not the best metaphor but in the world of soy sauce, you will always have dark and light. What differentiates these two are the taste that it carries in each bottle.
The dark soy sauce is usually a thicker liquid compared to the lighter sauce. It is also sweeter. It's sweetness ranges from plainly sweet to something that is more richer in taste, and a little syrupy in consistency as well as in taste. The thicker and syrupy consistency can either be used on its own or for marinates. Where as the medium and more lighter ones can be used as sauces. The more common soy sauce used in thicker Malay cooking are the ones with thicker consistency.
The lighter soy sauce is the saltier of the two, usually the lighter the colour, the more saltier is gets. Hence, sometimes using only a teaspoon of the liquid is enough to make a small pot taste and you won't even have to use salt. It can also be used as a dipping sauce on its own - with additional ingredients added to the mix - such as chopped garlic and scallions. A divine combo to dip with dumplings. This sauce is mostly used in Chinese recipes and also Thai dishes. However, there is also some thicker soy sauce that are salty and sweet in taste - this one can also be used for marinates, as a sauce on its own and used widely in making soy sauce based gravy dishes.
Even the English have their own soy sauce that is used mostly in soups and sauces - the old Worcestershire. Which is a bit more rounder in taste, it isn't exactly salty like the type used in Chinese recipes.
How to use it?
You can mix and match soy sauce with almost anything in the kitchen. Again the aim is to find balance between saltiness and sweetness.
Dark or thicker consistency soy sauce are usually more packed with sugar - it becomes more like molasses - therefore adding spices like ginger, galangal, cinnamon, pepper, five spice, fennel seeds or cumin to soy sauce creates a more robust flavor. This type of mix is most suitable more meaty flavours - a great match for beef and venison. You may also use dark sweet soy sauce mixed with coarsely ground cumin seeds and garlic to chicken or tempeh.
Light soy sauce is best when used with ingredients that are light in taste - it becomes a natural food enhancer for chicken, seafood and vegetables. For example, when you make wanton or gyoza mix, the base of the agent that binds the other ingredients together is the soy sauce. Steaming fish with ginger and tamarind, gives heat and sour taste to the fish, but dipping it into soy sauce, balances the sweetness from the fish and the sourness creating a delicious taste on your palate. You may also use dark soy sauce as a marinate for chicken and simply add honey and ginger to the marinate and leave it over night.
Storage?
Don't worry about storage because soy sauce is practically a fermented product, purchasing a bottle which could cost you less than a plate of mix rice in town - goes along way in your kitchen. Just be sure to store them away from sunlight and in cool places. Just be sure not to keep your soy sauce beyond the expiry date on the bottle, which usually is 12 months. Beyond that the sauce would be more acidic and that is an indication that you should chuck the old one out and bring in a new one.
