Miso’s quite a complex subject. The differences is miso can be attributed to a variety of factors, from the proportion of ingredients, cooking techniques, and duration and temperature of fermentation. The reddish color comes from long fermentation times (or in cheap imitations, from dyes). The whiter misos are generally fermented for short times, and often made with rice in addition to soybeans. Reds are generally saltier and whites sweeter.
Misos vary widely in fat content (like most soy products) and generally range from .25 to 1.5 grams of fat per Tablespoon (and from about 6%CFF to over 30%CFF). Some varieties, like peanut miso, obviously have even more fat. Since it is rare that a dish has more than 1 Tablespoon miso per serving, miso does not generally add appreciable fat to a dish. Many of the white sweet misos clock in at the low end (.25 grams per Tablespoon, 6-10%CFF) so if you do want to use more miso, these kinds can be added liberally to a dish (and since their taste isn’t as strong or salty, they do become many dishes in greater quantity).
The dark, hearty misos make great gravy starters. Add a bit of water/stock, some nutritional yeast, spices and a thickener to some miso and voila, instant delicious gravy.
On miso, you just have to try different kinds and brands. There are numerous styles of miso. Red misos tend to be more “savory” and white ones are usually more “sweet”.
Country-style (Inaka) is made grainier on purpose. If served as a sauce on veggies, probably it’s not straight miso but mixed w/sugar and some rice vinegar.
A warning to vegetarians, some misos come “dashi-iri” which includes fish-based stock. Some ingredients labels in English will mention fish, so check the ingredients carefully.
There is kombu-dashi which is vegetarian, but most dashi is from bonito flakes.
Keywords: Information, Tofu, Japanese, Accompaniments, Peanut, Rice, Barley