In today’s Japan Times, I have an article about the use of sakekasu, the lees (leftover bits) of the sake making process, in cooking. Sake is a fermented-grain beverage, not unlike beer, and sakekasu is a delicious and very useful by-product.
In the main sakekasu article [1], I also go into an explanation of why sake and mirin are used in Japanese cooking so much. This is a more detailed followup of sorts to my post here from 3 years ago, The role of alcohol, onion and ginger in Japanese meat dishes [2]. One of the main reasons to use sake or mirin in cooking is to get rid of the gamy flavor of meat or fish, but the other reasons are very important too, especially to draw out the umami in food. (This is why, even though you can use a bit of sugar in lieu of sake or mirin in recipes, sugar is not really a perfect substitute at all. The only reasons for avoiding the use of sake or mirin is if you can’t use either one for dietary or religious reasons, or if your country restricts their sale, even cooking sake or mirin, which are not really drinkable.)
If you’re in Japan, you can find sakekasu easily at supermarkets. If you have a favorite artisanal sake maker, ask them if they have some sakekasu to sell you - if you like their sake, you’ll love their sakekasu too. If you don’t live in Japan though, find it sakekasu a bit hard to come by. (Note that I orient my Japan Times articles and recipes to people living in Japan, who are the main readership for the paper, so I do write more about ingredients that may not be that easy to get outside of Japan. On my blogs I write mostly for a not-living-in-Japan audience.) If you live near a Japanese grocery store and don’t see it for sale, ask them if they have it or can get it for you. I have seen it for sale at a few stores, even at my Zürich ‘local’, Nishi’s Japan Shop. It will be in the refrigerated or freezer section, in bags or tubs. (Don’t confuse it wtih koji, which is a whole other thing.) Or, you may be able to buy readymade kasuzuke or fish marinated in sakekasu - I saw some delicious looking kasuzuke fish for sale at Shin Nippon-do in Roslyn, New York recently. I absolutely love kasuzuke; it has a wonderful aroma and distinct sweet-savory flavor. I prefer it over miso marinade, which has been popularized by Nobu and other places. I hope you can try kasuzuke, either homemade or storebought! The main Japan Times article has instructions for making your own kasuzuke. Narazuke, an ancient pickle that is a speciality of the city of Nara, is also something worth seeking out.
Here’s a photo of the grilled kazuzuke of kama or the fish head part of a large snapper. The fish head is the most delicious part of a fish, by the way, even if it looks rather funny.

The accompanying recipe [3] is for making kasujiru, a soup that uses sakekasu with a bit of miso. You can make kasujiru with 100% sakekasu too, but I prefer a bit of miso in this case. It’s hearty and very, very warming on a cold wintry night. Here’s another shot of it.

And yes, even though sakekasu does have alcohol in it, most of it evaporates with the heat of cooking, and Japanese children eat kasuzuke and kasujiru all the time.
As I mention in the article [1], recently there was a run on sakekasu in Japan because of a TV report that touted its health benefits…or to be specific, its cholesterol-lowering qualities, which got interpreted in the media as “OMG sakekasu is good for dieting whee!”, as often happens. (See also: The Natto Diet [4], which turned out to be a bogus story, and The Morning Banana Diet [5].) The source of the stories, a popular science-oriented program on NHK called Tameshite Gatten! (which roughly translates as Let’s Test It Out to Understand!) is a bit more credible than the natto and banana stories though. In any case, if you can get hold of sakekasu, I hope you give it a try!
Another use of sakekasu is to make amazake, a sweet, thick hot low-alcohol drink rather like eggnog. Amazake is consumed during the cold winter months - it’s thought to help ward off colds - and is a traditional part of the Girl’s Day Festival on March 3rd. Amazake is usually made from koji, steamed rice with sake-making spores, but using sakekasu is a lot easier and foolproof, if slightly higher in alcohol.

For 4 servings (4 cups)
If your sakekasu is rather solid, chop it up with a knife (it will be rather like soap). Or, just crumble it up with your hands. Put the sakekasu in a pot with the water, and allow to stand for several hours or overnight. The sakekasu will melt in the water - if it hasn’t melted totally, stir it around until you have a milky looking liquid.
Put the pot on the stove, and add the sugar. Stir while heating over a medium-low heat, until it’s warm and bubbling slightly. Add the salt and the grated ginger. Serve while hot with a spoon or chopsticks to stir while drinking.
Links:
[1] http://search.japantimes.co.jp/cgi-bin/fg20110128f1.html
[2] http://www.justhungry.com/the-role-alcohol-onion-and-ginger-japanese-meat-dishes
[3] http://search.japantimes.co.jp/cgi-bin/fg20110128f2.html
[4] http://www.justhungry.com/2007/01/the_great_natto_diet_rush_the.html
[5] http://www.webmd.com/food-recipes/features/the-morning-banana-diet