Kasuzuke (粕漬け, “lees pickles”) are foods cured in sake kasu (酒粕), the pale, fragrant paste left over when the fermented rice mash for sake is pressed. Vegetables, fish and meat are buried in a bed of kasu, sometimes sweetened and salted, and take on its sweet, savoury, faintly boozy aroma. The best-known kind is Nara-zuke (奈良漬), salted white melon, cucumber or other vegetables aged in sake kasu until they turn deep amber, a speciality of Nara.
What’s in Sake Kasu
Sake kasu is mostly the rice, koji and yeast solids that don’t end up in the sake. Per 100 g, Japan’s official food composition tables list about 215 kcal, 51 g water, 14.9 g protein, 5.2 g fibre, very little sodium (5 mg) – and 8.2 g of alcohol, plus vitamin B6 (0.94 mg) and folate (170 µg); vitamin B12 is listed as zero (MEXT). It comes as firm pressed sheets (itakasu), which soften at room temperature or with a splash of sake, and as softer, darker aged kasu, which is what traditional Nara-zuke uses.
That alcohol is the key to kasuzuke: together with salt, it keeps spoilage microbes down while the food slowly absorbs the kasu’s sugars and aroma.
How Nara-zuke Is Made
In the traditional process, the vegetables are first salted in a saturated salt solution, then repeatedly moved through fresh beds of aged sake kasu (more than 8% ethanol) for a year or more. Along the way the salt is drawn out and replaced by alcohol and flavour: finished Nara-zuke generally contains 5–8% salt and 6–10% ethanol. A 2025 study of Nara-zuke factories found that it really is fermented – by a single, unusual lactic acid bacterium, Fructilactobacillus fructivorans, whose Nara-zuke strains grew faster in 5–10% ethanol than without it and survived 15%. The same study dates the prototype of Nara-zuke to the early 8th century (Yoshioka et al., 2025).
Japan’s tables give Nara-zuke made from pickling melon 5.8 g of alcohol and 4.8 g of salt per 100 g (MEXT). It’s a pickle with real alcohol in it: eat it in small slices, not by the plateful, and don’t serve it to children or anyone avoiding alcohol.
Fish in Sake Kasu
Kasuzuke fish – salmon, cod, sablefish, mackerel – is salted, coated in sweetened kasu and left in the fridge for a day or more, then wiped clean and grilled. The kasu flavours and firms the surface, but it doesn’t cook or preserve raw fish, so keep it refrigerated and cook it through. The sugar in the kasu burns easily: grill it gently.
The most extreme kasuzuke is a Japanese regional speciality: the toxic ovaries of a puffer fish, salted and then cured for years in rice bran or sake lees. In a laboratory analysis, the tetrodotoxin in the cured ovaries fell to between a fiftieth and a ninetieth of that in fresh ovaries (Anraku et al., 2013). It’s a specialist product – never something to try at home.
Is It Good for You?
Sake kasu is a source of protein, fibre and some B vitamins. One small study gave 25–50 g of sake lees a day for six weeks to eight adults with constipation and reported fewer symptoms, but it had no control group, so it can’t show cause and effect (Tokumaru et al., 2025). Pickles from the kasu bed are salty and contain some alcohol, so treat them as a side dish. Cooked dishes such as kasujiru (sake lees soup) keep the flavour but not live microbes, and lose some of the alcohol.
For other Japanese pickles and ferments, see rice-bran nukazuke, umeboshi, shio koji and amazake, the sweet koji drink that’s sometimes made from sake kasu.