The solid matter, or total solids, in ketchup varies from less than 12 per cent to over 37 per cent. This means that the product varies from a substance having barely sufficient tomato added to give color and taste, to a rich, heavy tomato ketchup. The variation of total solids in any one brand is, of course, less, but large differences are not unusual. Three bottles of one brand showed a solids content varying from 12 per cent to 16 per cent, and seven of another brand varied from 32 per cent to 37.2 per cent. The amount of solids in a non-preservative ketchup should be not materially less than 28 per cent. It is necessary to have a rather high solid content for ketchup of this kind, so that it may keep after being opened on the consumer’s table. The variation in the insoluble solids is comparable to that in the total solids. The values for a number of samples examined in this laboratory ranged from .9 per cent to 2.3 per cent. As the insoluble solids come from the tomato pulp the amount of insoluble solids is to that extent an indication of the amount of tomato pulp used in the manufacture of the ketchup from whole tomato pulp. The consistency of the ketchup is dependent chiefly on the amount of insoluble tomato solids present. The ash usually varies from 2 per cent to 4 per cent, owing to the different amounts of salt, which varies in general from 1½ to 3 per cent. The acidity ranges from .4 to 2.3 per cent. The acidity is one of the most important factors in preventing the growth of bacteria and yeasts in the ketchup after being opened. In order to secure the best results the ketchup should have an acidity of over 1 per cent (expressed as acetic acid) and an acidity of 1.25 per cent or higher adds to the keeping quality of the ketchup after the bottle is opened. An increase in acidity will necessarily require an increase in the amount of sugar in order to secure the proper flavor; or, vice versa, an increase in the sugar will necessitate an increase in acidity. In some ketchups about one-half of the acidity is due to the citric acid of the tomatoes and the remainder to the vinegar added in manufacture. With ketchups of exceptionally high acidity, the proportion of citric acid to total acid may be much less than this. There may be considerable difference in the acidity in ketchup of the same brand due to variations in manufacture. The sugar present in the ketchup is derived both from the pulp and from the added sugar. In ketchup ranging from 12 to 30 per cent total solids, from 9 to 22 per cent of the solids may consist of sugars. METHODS OF MANUFACTURE