-------------------------------+------------------+------------------- Grammes in 100 c.c. | Gutedel (White). | Zinfandel (Red). -------------------------------+------------------+------------------- Alcohol | 10·45 | 9·80 Extract | 2·0908 | 2·1270 Mineral matter | 0·1978 | 0·2218 Volatile acids (as acetic) | 0·0804 | 0·0972 Fixed acids (as tartaric) | 0·4845 | 0·4110 Potassium bitartrate | 0·1579 | 0·1428 Free tartaric acid | 0·0060 | .. Other free acids (as tartaric) | 0·5850 | 0·5325 Sulphuric acid | 0·0384 | 0·0168 Phosphoric acid | 0·0220 | 0·0193 Chlorine | 0·0036 | 0·0054 Lime | 0·0056 | 0·0084 Magnesia | 0·0170 | 0·0160 Glycerine | 0·6133 | 0·5647 Sugar | 0·0165 | 0·0276 Polarisation | +0·2 | .. Succinic acid | 0·0068 | 0·0097 Malic acid | 0·0324 | 0·0922 -------------------------------+------------------+------------------- According to analyses made by R. Fresenius and R. Borgmann,[90] natural wine has the following _average_ composition:-- Grammes in 100 c.c. Alcohol 7·71 Extract 2·75 Free acids 0·73 Mineral matter 0·23 Glycerine 0·79 Sulphuric acid 0·038 Phosphoric acid 0·040 Lime 0·018 Magnesia 0·018 Potassa 0·092 Chlorine 0·004 Potassium bitartrate 0·200 Natural wines are frequently subjected to various processes of treatment, designed to remedy certain defects existing in the original must. While these do not, perhaps, all properly come under the head of adulteration, it is certain that many of the practices resorted to affect the dietetic quality of the wine in a deleterious manner. The most common modes of treatment, generally considered harmless, are the following:-- _Pasteuring_, which consists essentially in heating the wine to 60°, with a limited supply of air, and effects the artificial ageing and better conservation of the product. Wines which exhibit ropiness and other diseases are restored by destroying the fungi present. This is accomplished by subjecting the well-filled and corked bottles to a temperature of from 45° to 100° for several hours.