Caroenum

The identification of this particular liquor is difficult. It is likely to have been a grape must reduced by one-third and therefore similar to defrutum but thinner. Alternatively, it might also have been a sweet wine, some of which may or may not have been reduced to a similar degree before fermentation. A way out of this dilemma may be to find an inexpensive substitute, for example there are modern sweet wines which have cooked grape must added such as ‘Ambrato di Comiso’ from Sicily. However, I believe caroenum was a cooked syrup made at home. If a caroenum is made from a must taken from fresh grapes such as would normally be used to make a passum (i.e. a raisin wine) then the must would be sweeter than usual. And when one-third of its volume has been boiled away with two-thirds remaining it would be a thin yet flavoursome syrup. This is in contrast to the excessive sweetness, thickness and colour normally associated with defrutum. Caroenum was used in the recipes as a bulk ingredient rather than to flavour or colour; that was often the role of passum and defrutum. There are numerous sauces called oenogarum that contain no other form of ‘wine’ but caroenum and it could not therefore have been too thick or too rich. Andrew Dalby has pointed out that the original Greek term karyinos refers to a nut-brown colour, and this suggests to me that a white grape rather than a black one would have been the norm. To make a basic caroenum that will suffice for reconstructing these recipes, simmer a carton of white grape juice in a pan until you have lost one-third of its volume. Cool, return to the bottle and store. Alternatively, you can use the grape juice which you boiled to half its volume in order to adjust your fish sauce as a substitute for caroenum if you have made plenty. All these diverse wines and syrups – heavy raisin wine, rich and thick to add colour, and sweet thin syrups – were added to fish sauce and formed the basis of the ready-made sauce oenogarum.