“The best soy sauce is the one you grew up with,” says Izumi Nakayama, from the Institute for the Humanities and Social Sciences at the University of Hong Kong. Part of a group researching soy sauce in East Asia, her answer to the question of which soy sauce is best underlines how much the most mundane of foods and condiments are invariably linked to our earliest memories.
Soy sauce is a case in point. This condiment, ubiquitous in East and Southeast Asia and in countries rich with a significant diaspora from those regions, is so omnipresent that most people hardly pay much attention to it – yet each region has its own variation of it, and the more you explore the intricacies of soy sauce taste and production, the more it reveals countless facets of the history of food and taste, of technology and industrialisation, but also politics, sociology and, of course, culture and the local declination of all of the above.
Light and dark
Hong Kong has its own special traditions regarding soy sauce. The most characteristic one is that, like in southern Guangdong, food is prepared by blending two different types of soy sauce, mixed together in different proportions according to the recipes and the desired final flavour. One is commonly called light soy sauce, or saang1 cau1 (生抽), while the other is called dark soy sauce, or lou5 cau1 (老抽). There are a number of gradations for both categories, according to quality, length of fermentation, time of extraction from the fermentation vat, and manufacturers’ special recipes.
These two sauces are very distinctive. The first is lighter in colour, with a sharp and salty taste, and is characterised by a subtle nutty bean aroma. It’s very liquid and slightly translucent. Dark soy sauce is pitch black, and it is made with the addition of molasses, sugar, or caramel, according to the manufacturer’s own recipe (spices or flavour enhancers may also be added). It has a more syrupy consistency and an intriguing sweet and salty taste, made more complex by different layers of flavour.
“The two soy sauces are very integral to our cuisine,” says John D. Wong, associate professor at the University of Hong Kong, who analyses soy sauce in Hong Kong as part of a research group looking into the soy sauce of East Asia. “The combination of light and dark soy sauce is very specific to Hong Kong,” he says.
Soy sauce basics
If you want to orientate yourself among all the different bottles you see in Hong Kong’s supermarkets, it helps to have in mind a few basics. If you wish to taste the highest quality soy sauce, you should start by reading the labels of what you find, and discard those that list chemicals in their ingredients, as this means that the brewing has been accelerated through an artificially induced chemical reaction. “Premium” soy sauce, for example, called tau4 cau1 (頭抽), is the very first extraction from the vat of fermenting beans, and is considered the tastiest soy sauce – some will say this is the extra virgin olive oil of soy sauces.
Successive batches are made by adding more brine to the fermenting beans in the vat, producing a second extract. The term “double deluxe” or soeng1 wong4 (雙璜) can be added in front of either light or dark soy sauce, and it means that the sauce has been produced by fermenting the first extract twice, adding a new batch of inoculated beans, producing a high glutamate to soy ratio. “Gold label,” or gam1 biu1 (金標), which can also be added to either light or dark soy sauce, usually refers to the use of premium soy beans.
Then there are many types of flavoured soy sauce – seafood flavoured, lime or lemon flavoured, and many more, which usually mean a lower grade of soy sauce enhanced by natural or artificial flavourings. From this point on, however, since Hong Kong has not standardised the various grades of soy sauce, there can be a lot of differences in labelling between one brand and the other, and if you want to really discern what is what, you need to slowly familiarise yourself with the different types, and chose the one that you love the most.
“Brand labels are much newer than we think for local consumption,” says Wong. “Less than 50 years ago, people would still go with their own bottles and bags to buy soy sauce and rice at their favourite local shop. There was no label, it was those who bought from the wholesalers, or those who produced their own brand, who would decide the grade. In that era so much was in the shop owner’s own knowledge: if people asked them how best to cook something, they would sell them the sauce, the spices, and hand out a recipe, telling them to go home and cook it.”
How it’s made
Before looking more in depth at soy sauce in Hong Kong, we now need to set the scene for this savoury condiment. It is yet another declination of the all-powerful soybean, which has its origins in northern China, and is the protein powerhouse of the plant world. The high protein content makes it particularly well suited for fermentation, as the chemical process that is initiated by fermentation renders proteins more digestible and accessible by the human body.
The basic steps of natural soybean fermentation for soy sauce require first boiling the soybeans, which are usually then mixed with wheat or sometimes barley. At this point, they are inoculated with a starter, aspergillus oryzae, also known as koji mould, from the Japanese word for generic mould; the equivalent Chinese word for the most common starters is kuk1 (麴). This is a filamentous fungus that grows on rice and that will allow the breaking down of the bean’s proteins into amino acids. These are compounds that are vital for keeping the human body healthy and functioning, but that also produce that umami taste that we are so fond of.
The beans are then set on trays to dry, and after a certain amount of time — the exact amount varies from region to region and from manufacturer to manufacturer — the real brewing starts. The mixture is put into vats, into which brine is added, and left to be sunned for a few months, again with regional variations; as a rule of thumb, the longer the brewing time, the better and more complex the taste of the final product. Slowly, the beans will turn darker, and the liquid created by the fermenting beans and the brine is the first batch of soy sauce. After adding further brine for second and third extractions of soy sauce, the beans are spent, and some manufacturers will then mash them into a highly savoury bean paste used for stir-fries and other dishes.
Every region is different
The places that produce soy sauce all have slightly different techniques and recipes, which creates many variations in flavour. In Japan, for example, soy sauce is traditionally made in wooden barrels, although today this is usually limited to high-end artisanal production. Japan also brews tamari, a type of soy sauce that forgoes the need for wheat, making it suitable even for the severely gluten intolerant. “Japan has very specific standards to classify soy sauce, which are based on a number of different elements,” says Nakayama. “These are different from the regulations in Korea and Taiwan, regulating different types of production and ingredients.”
In the southern Chinese province of Fujian, soy sauce is produced without the addition of wheat or water at the fermenting stage, and the end product is a saltier brew without carbohydrates broken into sugars, making it taste a lot less sweet than other sauces. In Taiwan, different soy sauces use different technologies, but the most traditional product sees the use of black soybeans, which are indigenous to Taiwan. Their use was discontinued during the Japanese occupation (1895–1945), but is now being promoted again in the name of sustainability and biodiversity. The soy sauce produced is quite sweet, both through the addition of sugar, which helps the fermentation process by feeding the starter, and the specific taste of the black soy beans. Many Taiwanese producers will also add a hint of liquorice, or of aniseed, giving the sauce an even more aromatic flavour.
Given the size of China, it is no surprise that there are very many other variations across the country, from the sweeter sauces of Shanghai and the Jiangnan region, to the stronger, saltier ones from the north. Korea also uses two different types of soy sauce, but these are entirely different from what is used in Hong Kong: one sauce is called whe ganjang, or regular soy sauce, and the other one is josean ganjang, or soup soy sauce, a clearer and salty liquid that seasons a soup without darkening it.
What’s clear is that while soy sauce is first and foremost a condiment, it is also as a signifier of identity. And while the home cook may initially be satisfied with a one-type-fits-all bottle, the more you pay attention to it, the more you will want to make use of all the different possibilities and stretch your taste buds to appreciate a wider range of flavours.
This is the first of two parts. Check back next week for the second part, which will explore research into the origins of soy sauce and how it has evolved in Hong Kong.