Copyright 1999
Chapter 11
WINE YEASTS
The flavor characteristics of wine depend upon many factors. However, the yeast used for fermentation contributes little to the flavors of aged wine, and most flavor contributions from the yeast will be undetectable in wines aged in oak barrels for normal periods. Many other winemaking factors such as fruit quality, grape variety, the climate, fermentation temperature, lees contact, cap manipulation, etc. influence wine flavors much more than yeast.
Light bodied, fruity wines are exceptions. These wines are bottled and consumed when they are young, and the effects of the yeast are still noticeable. Under these conditions, subtle flavor and aroma variations can be produced by different strains of yeast.
YEAST CHARACTERISTICS
Large differences in wine yeasts do exist. However, these differences relate to properties other than creating wine flavors. Yeast characteristics important to winemakers include speed of fermentation, color extraction, how much alcohol is produced, tendencies to stick, the quantity of foam generated, hydrogen sulfide production, etc.
A few wineries use a different type of yeast for each wine produced. Many smaller wineries ferment all of their wines with only one or two types of yeast. The research winery at the University of California at Davis uses a single yeast type for all standard fermentations. Smaller wineries and home winemakers often use Prise de Mousse yeast for all their fermentations.
Yeast names often mislead and confuse novice winemakers. For example, Pasteur Champagne yeast is not very good for sparkling wine production. California Champagne or Prise de Mousse are better yeasts for the secondary fermentation of sparkling wines. Instead of implying use, the name shows the yeast strain originally came from the Champagne district of France. To complicate matters further, the same name is sometimes used by different yeast manufacturers to identify completely different yeast strains. A few years ago, two entirely different yeast strains of yeast were available commercially, and both were called "Prise de Mousse." When placing orders for yeast, winemakers can avoid confusion by providing the name of the yeast, the name of the manufacturer and the yeast designation number.
Recommended applications of several popular, dry yeasts are shown below.
YEAST TYPE |
White Wine | Red Wine |
Champagne | Stuck Fermentations |
| Montrachet | X | X | - | - |
| K-1 | X | X | - | X |
| Prise de Mouse | X | X | X | X |
| Pasteur Champagne | X | X | X | X |
YEAST TYPES
Wine yeast can be purchased in both liquid and dry forms. However, dry yeast is easier for small wineries and home winemakers to use. Some important characteristics of Lalvin yeasts wine are shown in the Table.
YEAST CHARACTERISTIC |
Montrachet | K- 1 |
Prise de Mousse | Pasteur Champagne |
| Ferment. Rate | Fast | Slow | Fast | V. Slow |
| Completeness | Good | Very Good | Good | Good |
| Alcohol Tolerance | 15% | 15% | 18% | 17% |
| Sugar Tolerance | Good | Good | Up to 34 Brix | Good |
| Optimal Temperature (C) | 20 | 20 | 15 | 20 |
| Temperature Range (C) | 15-25 | 15-30 | 10-25 | 15-25 |
| Alcohol Yield | High | High | Medium | N/A |
| Foaming | High | Low | V. Low | Medium |
| Flocculation | Normal | Normal | V. Good | Normal |
Epernay II
This is a popular yeast for producing light fruity style white and blush wines, and Epernay is also popular for producing wines made from fruit other than grapes. Sometimes Epernay is used for producing a light, fruity style Chardonnay wines. However, Chardonnay can be difficult to ferment completely, and stuck fermentation often results when Epernay yeast is used with Chardonnay. Chardonnay wines fermented with Epernay yeast should be closely monitored and tested for residual sugar.
Epernay is used at fermentation temperatures ranging from 50 to 70 degrees. Under these conditions, it produces slow, controlled fermentations, and volatile components in the juice are retained well. Excessive foaming is seldom a problem when Epernay is used. Epernay does not ferment well at low temperatures, and it is very sensitive to sudden changes in fermentation temperature (cold shock). Epernay yeast is often used when winemakers intend to leave some residual sugar in a wine. Usually, active Epernay fermentations can be stopped just by lowering the temperature of the tank.
Epernay yeast is sensitive to high alcohol levels. Consequently, Epernay should not be used in juices with high Brix values unless some residual sugar is wanted. Epernay yeast can produce very pleasant, fruity aroma characteristics in young wines, and home winemakers use Epernay yeast for fermenting fruit wines because of the fruity aromas produced. This yeast is available in five gram packets, 500 gram packages and in bulk form.
California Champagne (UCD 505)
This yeast is used primarily for the secondary fermentation of sparkling wines. It produces a simple, clean, yeasty fermentation, and these characteristics are desirable in most sparklers. After a reasonable aging period, UCD 505 yeast will flocculate into large clumps, and the large pieces of yeast are much easier to riddle. UCD 505 yeast is sensitive to alcohol and sulfur dioxide. To insure prompt, clean secondary fermentations, the free SO2 level of the cuvee should not exceed about 25 milligrams per liter, and the alcohol content should be less than 11 percent. Small quantities of yeast nutrient are often used with this yeast. UCD 505 is available only in 500 gram packages and in bulk.
Montrachet (UCD 522)
Montrachet was a very popular yeast for producing well-colored red wines and big white wines for many years. Montrachet produces strong, vigorous fermentations, and some type of cooling is often necessary in warm weather.
Unfortunately, Montrachet yeast often produces excessive quantities of hydrogen sulfide, and it has fallen into disfavor in recent years. Grapes low in nitrogen should always be augmented with a yeast nutrient or DAP when Montrachet yeast is used, and prudent winemakers make it a point to smell all Montrachet fermentations several times each day. Montrachet yeast should never be used with grapes containing residual sulfur dust. This yeast is available in five gram packets, 500 gram packages and in bulk.
Pasteur Champagne (UCD 595)
Contrary to its name, Pasteur Champagne yeast is not well suited for sparkling wine secondary fermentations. It can be used for sparkling wines, but UCD 595 produces very fine lees, and the light, fluffy lees make riddling difficult. Pasteur Champagne yeast is tolerant of high alcohol levels and sulfur dioxide, so it is often used to restart stuck fermentations. Some wineries use this yeast for both white and red fermentations, and it can be counted on to produce clean, neutral fermentations. When used under reasonable fermentation conditions, it seldom leaves residual sugar. Sometimes Pasteur Champagne yeast produces large quantities of foam in warm weather. This yeast is available in five gram packets, 500 gram packages and in bulk.
Prise de Mousse (E.C. 1118)
Since it became available in dry form several years ago, the popularity of Prise de Mousse (PdM) yeast has increased rapidly. PdM is an excellent, general purpose yeast for both red and white wines. It produces low hydrogen sulfide fermentations, and it ferments vigorously. Since this yeast usually produces a dry wine, it is one of the more popular yeasts for California Chardonnay production. This yeast is tolerant to sulfur dioxide, and it is tolerant to high alcohol levels. Consequently, Prise de Mousse is useful for restarting stuck fermentations. Prise de Mousse is also used for the secondary fermentation of sparkling wine. Under normal condition Prise de Mousse produces little foam and seldom causes the winemaker any trouble. Smaller wineries often use this yeast for all their fermentations. PdM is available in five gram envelopes, 500 gram packages and in bulk.
Steinberg
Steinberg yeast is used for producing classical, "cold fermented" Riesling wines, and it is used extensively for Gewurztraminer production. When used at low fermentation temperatures, Steinberg produces a delicate, complex bouquet of fruit odors in young white wines. This yeast is very cold tolerant, and it often continues fermenting at temperatures below 40 degrees. However, this yeast is very sensitive to sulfur dioxide, and Steinberg fermentations can be retarded significantly if more than 50 milligrams per liter of sulfur dioxide are added at the crusher. Sometimes, winemakers can deliberately stop low temperature Steinberg fermentations just by adding a large dose of sulfur dioxide to the tank. This yeast is only available in 500 gram packages and in bulk.
Pasteur Red
Pasteur Red yeast has been available commercially for some time, but it has only been produced in dry form for the past several years. In dry form, Pasteur Red is rapidly becoming the yeast of choice for producing full-bodied red wines. Pasteur Red produces clean fermentations, and it has good color extraction characteristics. This yeast seems particularly well suited for fermenting deeply colored "Bordeaux" style red wines. Pasteur Red yeast is vigorous, and some cooling is often needed in warm weather. Pasteur Red yeast can be purchased in five gram packets, 500 gram packages and in bulk form.
SUMMARY
The type of yeast used for fermentation has little influence on the aromas and flavors of aged wines. However, yeast can contribute to the aroma of young, fruity wines.
Yeast is available in liquid and dry form, but dry yeast is much easier for small producers to use.
Prise de Mousse yeast produces little foam and seldom causes fermentation problems. Some small wineries use Prise de Mousse for all of their red and white fermentations, and it can be used to restart stuck fermentations.
Click here to return to Contents