Romanian Lenten Bean Sour Soup (Ciorba de fasole de post)

Normally the bean soup (‘ciorba de fasole’) is made with smoked pork knuckle, but this is the simple Lenten version, without meat. The ‘ciorba’ is traditionally soured with borş (fermented wheat bran) and scented with tarragon and thyme, Transylvania style, or with parsley, as they do in Southern Romania.