From the producer:
When you make things from scratch like Iio Jozo does by making sake first, then fermenting that into vinegar, naturally you will have some by-products. In sake making the by-product is called sake kasu (sake lees). Iio Jozo decided to take their sake kasu and basically ferment it into vinegar. Sounds simple enough, right? But Iio Jozo ages it for 10 years before they call it Akasu (red vinegar). This special brew is very different, almost like a tame sherry vinegar crossed with rice vinegar. Top sushi chefs use it in their rice, but we find it amazing in many other way - think pickles, vinaigrettes, etc.
Ingredients: water, rice, aged sake lees
360 ml glass bottle