This is the fifth and final installment of my monthly column in Chengdoo Citylife Magazine, 'Your Chuancai Cupboard'. This month: Vinegar.

Vinegar, 醋， is among the most important condiments in Chinese cooking. One of the so-called ‘Seven Essentials’ of the traditional Chinese kitchen (along with firewood, rice, oil, salt, soy sauce and tea), vinegar’s importance in Chinese culture even extends to the language – in Mandarin, ‘to eat vinegar’， 吃醋， means to be jealous of somebody or something.

Vinegar is said to have been invented in China during the Xia Dynasty in around 2000 BC, and has been commercially produced from as early as the 1st century AD. It is particularly prized for its sourness (one of the four essential tastes, along with salty, sweet and bitter), and it is also widely used in Traditional Chinese Medicine for the treatment of all manner of ailments, from high blood pressure to athlete’s foot; TCM practitioners use vinegar to promote warm (yang) energy, and it is said to be particularly effectively when eaten in autumn.

Though commonly referred to as rice vinegar, Chinese vinegars are in fact usually made from a combination of ingredients that often includes rice (both white and black), but may also utilize wheat, millet, and sorghum. The color of Chinese vinegars ranges widely, from clear to inky black, and so too does the taste, from strongly acidic to smoky and mild.

Sichuan is one of China’s four most famous producers of vinegar; the other three are Zhejiang, Shanxi, and Fujian. Sichuan’s capital of vinegar production is Langzhong, in the northeast of the province, where, unique among Chinese vinegars, bran is the primary ingredient.

Baoning vinegar is the most famous and widely used brand made in Langzhong, but others do exist – I particularly like that made by the Langzhou 朗州 company, which is sweeter than the Baoning variety. At the Langzhou Vinegar Company, the traditional method of production is still in use, and goes as follows.

First, rice and dried corn kernels are steamed, and then are added to a mixture of bran and over 60 traditional Chinese medicines and herbs. This mixture is then left to ferment in sealed containers for up to 60 days, then is mixed with spring water and seeped for 2 to 3 days. Finally, the liquid is strained, boiled, bottled and is thus ready for use.

Though not as commonly used in Sichuan’s cuisine as in other parts of China, vinegar is nonetheless an indispensable part of the Sichuanese kitchen. Black vinegar is more commonly used than white vinegar, but the latter does feature particularly in cold dishes. Black vinegar can be bought at dried good stalls at markets, while supermarkets usually stock a wide variety of many different types. Outside of China, Chinkiang vinegar, widely available in Oriental supermarkets, is an acceptable substitute.

Perhaps the most famous Sichuanese dish that uses vinegar is the ridiculously easy Tiger-Skin Peppers， 虎皮请教， pictured above. Below is a recipe I’ve adapted from Fuchsia Dunlop’s Sichuan Cookery; the size of green pepper you use for this dish can vary – if you like it spicy, go for the long, thin ones; if not, go for a larger variety.

Tiger-Skin Peppers 虎皮请教

4 green peppers (capsicum)
Cooking oil
1-2 tablespoons black vinegar
1/2 teaspoon sugar
Salt to taste

1. If using large green peppers, quarter and discard the seeds and stems. If using the small kind, just squash slightly with the side of your cleaver. Mix the sugar and salt into the vinegar until they are completely dissolved.
2. Heat about 2 tablespoons of oil in a wok until smoking, and then add the peppers. Stir-fry over a medium heat for 5-6 minutes, or until the peppers are tender and their skins blistered and streaky.
3. Finally, remove the peppers to a serving dish, drizzle with the vinegar mixture and serve.

Here is the fourth installment of my monthly column in Chengdoo Citylife Magazine, 'Your Chuancai Cupboard'. This month: Ya Cai.

Ya cai, is one of Sichuan’s most famous and distinctive food products. Made from the stems of a variety of mustard green, it’s fragrant and distinctive flavor is found in many of the regions dishes. Said to have been invented in the early 19th century, ya cai is just one of the myriad different preserved vegetables used in Sichuan’s cuisine, including zha cai, da tou cai ('big head vegetable')and many other regional varieties.

Ya cai’s primary ingredient is jie mo cai, a type of mustard green native to Southeast Sichuan. Around 4-5 months after being planted, the mustard green plants are harvested in the 9th lunar month. The leaves are then discarded, the stems sliced into even strips, and the strips hung out on poles to dry.

The making of ya cai is unusual among Sichuanese ingredients, in that while doubanjiang (chilli bean paste) and dou chi (fermented black beans) only require one fermentation stage, ya cai demands two. Once sufficiently dry, the mustard green stems are mixed with salt and left to ferment in sealed containers for 3 to 6 months – small ceramic pots called tu tan are traditionally used. This is the first of the two fermentation stages.

Once the first stage is complete, the mustard green stems are boiled with brown sugar for 8 to 9 hours, and are hung up to dry out once more. Now, star anise, Sichuan pepper, and other spices are added, and again, the mustard green stems are left to ferment in sealed containers for another 3 to 6 months.

In Chengdu’s markets you can sometimes find un-cut ya cai – long, straggly strips of green-brown vegetable, bought by weight – but mostly ya cai is bought already chopped up in small, sealed packages. When buying ya cai make sure to buy a brand based in Yibin, the city about 250km southeast of Chengdu which is the most celebrated producer of this ingredient. Once opened, you should store ya cai in a sealed container in a cool, dry place.

Though a few different brands exist, by far the most common is Yibin’s Sui Mi Ya Cai Company, who apparently started the practice of chopping up ya cai, hence the name – sui mi means crushed rice, referring to the appearance of the company’s bitty, pre-cut ya cai.

Ya cai is often mixed with pork for the stuffing of baozi, and is also a vital ingredient in Yibin’s signature dish, ran mian (‘burning noodles’). But it is perhaps most famously used in one of Sichuan’s most popular vegetable dishes, Dry-Fried Green beans. I’ve eaten countless different versions of this dish, but this one is my favorite.

Dry-fried Green Beans

250g green beans
2 tablespoons ya cai
1 tablespoon fermented black beans (dou chi), rinsed and drained
5 dried chillies, halved and seeds discarded
1 teaspoon Sichuan pepper (huajiao)
3 cloves of garlic, thinly sliced, and the same amount of ginger, thinly sliced
3 spring onions, cut into 3cm lengths
50g minced pork (optional)
Cooking oil
Salt to taste

1. Top and tail the green beans, and cut into 5cm lengths.
2. Heat your wok, and add about a tablespoon of cooking oil. Once hot, add the pork and stir-fry for a few minutes until cooked through, and then set aside.
3. Add a tablespoon of oil to the wok, and once hot add the beans, stir-fry for a couple of minutes, and then add another 1-2 tablespoons of oil. Stir-fry for another 3-5 minutes, or until the beans are tender. Remove from the wok and set aside.
4. Add another tablespoon of oil to the wok, and once hot add the garlic and ginger slices. Stir-fry on a moderate heat for about 30 seconds, and then add the chilies and Sichuan pepper. Stir-fry for another 30 seconds, taking care not to burn the spices, and now add the ya cai and dou chi and stir-fry for another 30 seconds.
5. Finally, add the spring onions (and the pork, if using), and return the beans to the wok. Stir-fry for another minute or so, add salt to taste, remove to a serving dish and serve.

Greetings from Vietnam! Yep, here I am in another People's Republic, soaking up the differences in Sapa. Though I've only been in the country less than 24 hours I've already eaten a fantasic snack, which I will write about soon no doubt. But before I do, I want to talk about the noodle dish you see above, which I ate in Kunming the other day.

As I was preparing to cross one border, this dish was crossing another. Served at a restaurant specialising in Tengchong cuisine, I could taste the the proximity of Burma's very different food in every mouthful - and, since I have almost no familiarity with that country's food, I am hard pressed to know how to describe this dish. The noodles were different to any I've had before, and it was served with all manner of mysterious sauces. I have no idea what was in it, but boy it was yummy.

Bamboo Paradise, Langzhong market.

I just got back from Langzhong, where I'd hoped to learn about the famous local vinegar. Though I wasn’t entirely satisfied by the trip in this respect (commercialization of vinegar does not an open process make, it turns out), the town’s wonderful market totally charmed me and more than made up for the pitfalls with the vinegar. Here are a few scenes from a cold but sunny morning.

Concentration.

Another famous local specialty, Chuan Bei Liangfen (North Sichuan pea jelly).

I've never seen tofu as yellow as this before.

The fried noodles in the foreground are crumbled over beef gravy, yet another local delicacy.

The ginger and garlic man.

Today as I was showering in my local municipal pool after a swim, my nostrils caught the unmistakable whiff of vinegar. I'd smelt vinegar here before, and had always assumed that it was being used to clean the drains or something. Today though, when I looked around for the source of the smell, I noticed a tiny old lady pouring capfuls of a dark liquid from an old soft drink bottle onto her hair.

'Is that vinegar?' I asked her, to which she answered 'Yes, it's very good for your hair!'

After a little Google sleuthing I came across this article, which states that rinsing with vinegar leaves your hair 'shinier, smoother, and easier to manage'.

Seeing as I'm heading off to Langzhong, Sichuan's vinegar capital, tomorrow morning, maybe I should try it out for myself; unlike some other alternative uses for food that I've seen...

UPDATE: My very own mother has just emailed me saying that when she was 'a young lass' (her words not mine!), she frequently used vinegar in her hair to help it shine - so there you go.