Wine is one of the oldest alcoholic beverages known to man. Recorded history shows that, as far back as 12,000 years ago, man had discovered the art of winemaking. Early Egyptians are known to have enjoyed wine. In fact, wine gained such prominence in this time that it almost developed into an industry of its own. Even though wine was already being made as far back as 2,000 B.C, wine yeast was only discovered in the 1850’s by French scientist Louis Pasteur. He suggested that the fermenting of wine was due to the presence of a living organism.
Thanks to this discovery so many years back, now we use wine yeast for winemaking. Yeast has an important role when it comes to making wine. It is the element that turns grape juice to wine. Wine yeast is a unicellular type of fungi that can be found on the skin of wine-making grapes. The organisms are fermentative and can consume a number of sugars. Some of the common yeast varieties that occur naturally on grapes include genera like Hanseula, Kloeckera, Saccharomyces, Hanseniaspora, Candida, Brettanomyces and Pichia.
The Fermentation Process
The common belief is that spontaneous fermentation in the non-Saccharomyces yeast genera, such as Hanseula and Kloeckera, starts at the beginning stages of fermentation. As fermentation continues, the alcohol content rises. The non-Saccharomyces are unable to continue with aggressive growth. At this point, the native Saccharomyces yeast take over fermentation.
There are those who prefer natural fermentation over pure yeast strains for the various flavors the wine acquires during the process. Others that prefer to control the whole process feel like spontaneous fermentation is too unpredictable and may introduce odors into the wine.
Those who believe in inoculation by pure strains of yeast assume that the introduced yeast strains are going to carry out fermentation. However, research shows that even in this case, the native Saccharomyces and non-Saccharomyces take part in the fermentation process.
Other Products of Yeast in Wine
Alcohol is the prominent by-product of yeast when it comes to wine making. Yeast can be used to provide several other products can also affect the final condition of the wine. One component is glycerol, which is produced by the reduction of dihydroxyacetone, which is an intermediate of the glycolysis cycle. Glycerol improves the body of the wine and gives it a slightly sweet taste while keeping the alcohol level unchanged. For this reason, there are winemakers that like to make their wine in conditions that favor the production of glycerol.
Pectins also produce methanol through demethylation by yeast enzymes. This occurs more in red wines than white wine, although in inconsequential amounts. When amino acids decompose, they form fuse oils, such as 2,3-Butanediol, which has a neutral smell. Winemakers are known to add yeast to wine that is too buttery. Yeast consumes diacetyl, reducing the buttery aroma. Other components produced in the wine making process include acetaldehyde, pyruvic acid, hydrogen sulfide, succinic acid and acetic acid.
The Difference Between Wine Yeast and Bread-Baking Yeast
You may be wondering whether you can use normal bread baking yeast for your homemade wine. The answer is that the two are quite distinct. Some of the main differences have to do with their purpose of being bred. Here are some of the main differences;
- Wine yeast is mainly intended for the production of high levels of alcohol, thus lower carbon dioxide levels.
- The packaging for bread yeast is at food-grade level. Wine yeast on the other hand is packaged in sterile conditions since it is associated with long-term fermentation periods.
- Wine yeasts are high tolerance strains that have the special ability to remain active up to levels as high as 17% alcohol.
- More often, wine yeast can stay stable in environments with sodium metabisulfite, a staple in wine making.
- Compared to bread yeast, wine yeast clears must quicker and does not foam as much when fermenting.
Where to Buy Wine Yeast
Over the years, yeast has been developed such that you can acquire all strains commercially. Suppliers such as Cider House, Craft Series, SafCider, Red Star and Lalvin have various strains of wine yeast that you could use for your home-based brewing. These are yeast packs of 500g that go for anything between $1 and $50, depending on the kind of yeast you are looking for.
Those in large scale production, or just need more than 500g packs, can also get their yeast from suppliers.
American Suppliers of Wine Yeast
- The Wine Lab, 477 Walnut St., Napa, CA 94559. (707)224-7903.
- Cellulo Co., 2949 E. Townsend Ave., Fresno, CA 93721. (209)485-2692.
- Presque Isle Wine Cellar, 9440 Buffalo Rd., North East, PA 16242. (800)488-7492.
- Scott Laboratories, 2220 Pineview Way, PO Box 750249, Petaluma, CA 94975. (800)821-7254.
- Vinquiry, 16003 Healdsburg Ave., PO Box 695, Healdsburg, CA 95448. (707)433-8869.
- Universal Foods Corp., 433 East Michigan St., Milwaukee, WI 53201. (414)347-3886.
For a quick-buy of yeast to try, Amazon has a variety of wine yeast options! From this 10-pack of dry wine yeast, to this 11-pack from Red Star! But before you go-forth and make your purchase, click this link to sign up for a FREE 30-day trial of Amazon’s Prime Membership— an exclusive offer for our Wine on My Time community in lieu of our sponsorship from Amazon. Enjoy!
The Use of Pure Yeast Cultures
Alcoholic fermentation using pure yeast cultures has well-known advantages. Yeast can be used as a liquid culture or alternatively as dry wine yeast. Liquid yeast starter takes a lot of work to make and needs specialized equipment. It is not an option you can use in a small-scale brewing operation.
Advantages of Pure Yeast Culture
- Better control of the fermentation process
- Quick onset of the process of fermentation
- Can depend on certain characteristics of yeast for a deliberate result in the final wine
- Consistent wine production with a set quality
- Curbs the possibility of the wine developing ‘off-flavor’
By now, you may have realized that yeast plays a huge role in the whole winemaking process. Different wine types have specific yeast strains. When making your own wine, you would be well- advised to find out all you can about the type of yeast to use. If you make wine and use another supplier, let us know in the comments where you buy your wine yeast!
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