The Growth and Fermentation Characteristics of Six Yeast Strains at Several Temperatures

¹ Estacão Agronómica Nacional, Oeiras, Portugal

The influence of four increasing temperature ranges on S. cerevisiae, "Burgundy" and "Montrachet" strains, S. oviformis, S. fragilis, S. marxianus, and Sch. pombe on cell growth (for the first three strains) and on alcohol and volatile acidity production was studied. Conclusions were as follows:

1. The best yeast cell growth was made at a constant temperature of 30°C for all strains. At temperatures of 30-34°C a marked decrease was shown, and at higher ranges no growth was found.

2. The best temperature for alcohol production was also shown to be at 30°C, and the "Montrachet" strain produced the highest amount. At temperatures of 30-34°C the alcohol production was about the same, except with S. marxianus, which decreased in alcohol production. In the tests at higher temperatures, decreases in alcohol production were marked. The highest tolerance was shown by Sch. pombe, and the lowest with S. fragilis. As a general rule, one may say that alcohol production becomes proportionally lower at successively higher temperatures.

3. The volatile-acidity production increased with temperature except for Sch. pombe, which showed lower production at higher temperatures. At 30°C the lowest volatile acidity was produced by the "Montrachet" strain, and the largest amount by S. marxianus.

4. The "Montrachet" strain has the better wine-making characteristics if growth, alcohol production, and low volatile acid formation are taken as criteria.