Baijiu basics: sour mash

Having discussed the different styles of baijiu and the basic fundamentals of fermentation, I’d like to turn our attention to the actual business of making baijiu. Every brand has its own tricks, but one popular method in southwestern China is what’s called continuous fermentation, or sour mash. If this sounds vaguely familiar to American readers, it’s because we love sour mash in the States – it has a long, proud history with Bourbon and Tennessee whiskey.

When you are making grain alcohol you combine mashed grains with a fermenting agent (yeast in the West, qu in China, and then the fermenting agent converts sugars to alcohol. The alcoholic liquid is then heated until it vaporizes, the vapor is collected in a receptacle and then it’s cooled back into a liquid with much higher alcohol content – the process known as distillation.

Sour mash is the process by which a previously fermented batch of grain mash (or simply “mash”) is reincorporated into a fresh mash. The sour mash process is not dissimilar from the process of making sourdough bread, where a piece of the previous loaf starter is reused in the next. The thinking behind sour mash is that it not only creates a better tasting drink, but it also ensures a degree of continuity between batches.

Two of the best known practitioners of sour mash in the baijiu world are Luzhou Laojiao 泸州老窖 and Maotai 茅台, but their techniques vary.

Luzhou uses a technique they call “thousand-year mash” that ferments the grain in a 4:1 ratio of old to new mash. After distillation the mash is put back into the baijiu fermentation pits (more on these later), where residual liquid will be allowed to soak into the soil.

Maotai starts off its process with a fresh mash that is immediately distilled after a month-long fermentation. The resulting distilled liquor is mixed with the used mash and allowed to ferment a second time. Then more raw materials are added at a 1:1 mash to sour mash ratio, the combination is fermented, distilled and mixed with more raw materials. And so on until eight fermentations have taken place, and the resulting liquor is aged for 3 to 20 years in barrels.

Though its still widely practiced in the United States, I have heard that advances in modern distillation methods have made sour mash of negligible importance in whiskey making. Baijiu may be another story, because its production uses fermentation and distillation methods that have changed little over hundreds, perhaps thousands, of years. It’s a fascinating topic (to me at least), but I’ve rambled on enough for one post, so baijiu distillation methods will be covered in the next “baijiu basics” installment.

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9 Responses to Baijiu basics: sour mash

  1. Ted says:

    Thanks for a fascinating blog. As a great lover of whiskey (as well as baijiu) I thought I should add a couple facts to this discussion of sour mash.

    As you note, the sour mash process involves adding back the previously-distilled grains and mash, after the spirits are separated from them, back into the mash container as part of the next batch. While there are probably some benefits in terms of taste consistency, that’s not the main reason that distillers use a sour mash process. Consistency can be achieved as easily by repeating a recipe exactly, or by mixing the distillate from numerous batches over time, instead of mixing the spent grains and backset. (“Backset” is a term for the liquid left in the still after the bulk of the ethanol has been extracted from it.)

    Whether we are making baijiu or Scotch whiskey, the processes start out the same: we first try to convert the grain starches into sugar, so it can be fermented by yeast. This conversion from starch to sugar is accomplished by enzymes, mostly alpha amylase or beta glucanase, but there are probably dozens of others at work as well. In baijiu of course, these enzymes are produced by the aspergillius orzae mold that grows in the qu. If you are making Scotch, the enzymes come from the barley malt. The enzymes then attack the grain’s starches and convert them to sugar.

    Sour mash developed mostly as a way to create the best possible atmosphere to encourage the work of the enzymes in the saccarification process. The enzymes work most efficiently when the PH level in the mash is slightly acidic. Since backset is slightly acidic, and most water sources are slightly alkaline, early distillers learned to add the backset to the next batch of mash in order to adjust the PH in the mash barrel.

    I’m experimenting with my first batch of sorghum and qu now. I have a mash fermenting in buckets, using two forms of qu I found at asian groceries in the US. When I think it’s ready, I’ll have a friend with a distillery run it through his still for me, and see if it tastes anything like baijiu.

    Keep up the blog!

    • Mike Hu says:

      Hey Ted,
      Did your baijiu work? Would love to know.

      • Ted says:

        Hey Mike!
        My baijiu turned out just lovely. I don’t claim to have sampled enough to be any sort of expert, but it tastes like baijiu should, and I’ve begun making it regularly. It tastes most like a baijiu I received as a gift in Inner Mongolia, and I understand it was a local product, but I don’t read enough Mandarin to know a name for it.

        It’s a very much slower process than making whiskey, but it requires about the same total work in the end, just a longer wait for fermentation. I used the sorghum seed grain sold at the local feed store, ground it into meal, just like I would the barley or corn for whiskey, then boiled it with water (two pounds per gallon). After it cooled, I added two types of qu that are sold at the local Korean grocery. One came it a bag that looked like some kind of ground grain, and apparently had the qu growing on the grain. The second version was sold in one-inch sphere-shaped pellets that I crushed before mixing them into the mash. Seal it up with an air lock and let it sit in plastic buckets for several months. Filter out the grain, distill the mash, and you have passable baijiu. Good stuff!

      • Mike Hu says:

        Hi Ted,

        Thanks for the great reply.

        I’d love to be able to make my own as well. A few more questions;

        1. Which aroma would you say you produced? Strong or sauce or light?

        2. What kind of distiller do you use?

        3. What percentage alcohol comes out at the end? and do you dilute it with water?

        Thanks

      • Ted says:

        I don’t know enough to tell you which aroma I produced. My guess is that you could study common baijiu varieties made primarily with sorghum seed to find out. Known varieties made with the same grain should produce similar flavors.

        The still we used is a leftover from the days when my distiller friend was learning his craft. While he now has huge professional stills, we distilled my mash using a simple potstill setup made from a 15 gallon beer keg as a boiler, fitted with a still head made from open copper pipe. While my friend’s still is a slightly different design, it looks basically like this one: http://homedistiller.org/image/bujapat1.jpg It would be easy to build one, and the website that hosts that image (homedistiller.org) has a forum with lots of information about building your own distilling equipment. (they even have a couple threads about making baijiu, though the site’s recipes are mostly for various corn whiskies.)

        I run the mash through the still twice. The first run comes out roughly 40 percent alcohol, running the still rather hot to strip the alcohol out quickly. Then I run the alcohol through again, at a much slower rate (lower flame) and the result is roughly 50 to 70 percent alcohol. I add water to bring the final product to 50 %.

  2. Derek says:

    Hi gents, been following your distilling conversation with great interest and thought I would weigh in for a moment.

    Ted: you are to be commended for making what sounds like an excellent baijiu. I am deeply impressed and only wish that I could try it. Did you take any pictures of the production process? I would love to throw a detailed description of your experiment up on the blog for others to admire/replicate.

    Mike: Based on Ted’s description I would say this sounds closest to a small-qu light-aroma baijiu (assuming the Korean qu—what they call “kook”—was rice-based). If you want to try something similar, I recommend a brand called Jiangjin from Chongqing. There’s a post about it floating around here somewhere.

    Anyways, greatly amused by this exchange. Keep fighting the good fight.

    • Mike Hu says:

      Hi Derek,

      Huge admirer of your blog and book. I was China last month and I read your book. I’m from Guiyang and Chongqing myself and only recently started to pay attention to the baijiu I’ve encountered throughout my life.

      I would really love to be able to produce strong aroma as I think I’ve settled on that as my favorite. Of course I’d be very keen to see this blog continue and possibly into a “how to make baijiu at home path”. This is pretty much what the small producers in China do right? I would dearly love to be able to replicate Ted’s success in the UK where baijiu is scarce to say the least.

      I’ve even come across some very passable brandless small brewers sauce aroma in Guiyang and I am fascinated as to how this can be done on a small scale given the labour intensive methods you have described Derek.

      Anyway, looking forward further insights…

      • Ted says:

        Derek,

        I’ve never taken photos of the brewing process, but I’d be happy to do that with my next batch. I only wish I could share the flavor with you, and have you explain which variety I’m making. I like to think I’ve sampled a good deal of baijiu, but I don’t claim to know much about the varieties. I wish I could get together with you for a tasting! If you’re ever in Colorado . . .

        I’d be happy to take photographs of the brewing and distilling process, if you’d like to post a blog entry, Derek. It might be of some interest to baijiu lovers who are stuck living where the stuff is not sold. That’s the situation that led me to try making my own.

        I should be able to put together a batch in the coming weeks, and I’ll document the mashing process. Sadly, it won’t be traditional: there will be no dirt pits involved!

        Give me an email address and I’ll send the photos and a narrative of the process.

  3. Derek says:

    I was just in Colorado a couple of weeks ago. If only I had known! I can be reached at: derek [at] sandha [dot] us

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