Put your ear to that glass of wine in hand. Can you hear the tiny voices shouting, “Hey, what about some small credit for us here?” From one point of view, the producers do not make wine, yeast and bacteria. Juice into wine by the miracle of fermentation, the conversion of sugar into alcohol and other compounds. Since I have yet to see a human being sugar and alcohol drinking cough producers must delegate this key operation to yeast.
It is fair to say that these bodies fermenting underappreciated players in the winemaking team, at least in the eyes of the public. Moreover, what about the parade of yeast and other bacteria those manipulate, for better and for worse, the sensory characteristics of our favorite drink? And so in the spirit of recognizing the great team players and very, very small, meet the ten most common errors and their interesting wine.
1. Saccharomyces cerevisiae – whether microbes had titles, this yeast Chief Winemaker. Although other yeast can help get the process moving, S. cerevisiae is the worst part of the work in almost all fermentations. If you think you do not earn enough credit for this work, we believe that what we call “fermentation” is just eating from the point of view of yeast: yeast use the sugar in grape juice as food and excretion ethanol as a waste product. Some other interesting facts about this error:
* S. cerevisiae is present in very small quantities, in any case, the grapes in the vineyard.
* The same species of yeast are used for both wine and bread yeast.
* Saccharomyces literally means “sugar fungus.” Yeasts are fungi, and it lives on sugar.
2. Lactobacillus – as oeni, Lactobacilli are lactic acid bacteria. Unlike oeni, most of these errors are cousins deterioration make their presence felt very unpleasant. Lactobacillus kunkeei, alias “Lactobacillus fierce,” can destroy the nose of ferment in just 48 hours. Fructivorans Lactobacillus, also known as “mold Fresno,” can fill a bottle of wine with strands of cotton like candy. And hilgardii Lactobacillus may be responsible for the aroma of dead mouse that affects the rare bottle of red. Yes, a dead mouse. Several Lactobacillus species have also been blamed as the cause of a stuck fermentation. Not all lactobacilli are evil, however. Some strains can be used for malolactic fermentation, and markets Lallemand malolactic starter culture Lactobacillus plantarum based.
3. Schizosaccharomyces pombe – this yeast is of interest to microbiologists, and that reproduces by fission, or split in half, hence the “schizophrenia” nickname. (The “pombe” part of the name, incidentally, comes from the millet beer since it was first isolated;. “Pombe” means “beer” in Swahili) Schizosaccharomyces is very attractive to winemakers, however, because has the unusual ability to metabolize malic acid to ethanol. This could be a good thing, what would happen if a winemaker can take the edge off a too acidic due to throwing some S. pombe? Unfortunately, S. pombe has an offensive manner of production of flavors, too. One solution might be to limit the time spent in the must, or what people suggest Lallemand. His “to reduce the acidity of fruit juice” is essentially a giant tea bag full of S. pombe. Suspend the bag on her should, control the pH, and pull the bag after the pH has risen, but before a scandal arises.
4. Oenococcus oeni (relatively new designation for Leuconostoc oenos) – these bacteria play in our team assistant winemaker microbial. O. oeni are lactic acid bacteria, which means they produce lactic acid as a byproduct of their metabolism. Along with his ability to use malic acid for energy, this means that O. oeni can malolactic fermentation, the “conversion” of malic acid into lactic acid. Malic acid is a stronger acid than lactic acid, which means that the malolactic fermentation reduces the acidity (and raises the pH) of wine, softening hard edges, while adding different flavors. In summary, we have O. oeni to thank some of the roundness of Cabernet and some of the qualities of butter (a lot) Chardonnay.
5. Brettanomyces – “Brett” if you want to start a heated discussion between a group of wine lovers, the yeast can mention this perfume with notes of a wine range of sweat and animal waste water or infused with interesting aromas of leather and spice. Some are wine-lovers in mind that a “Bretty” the wine is a flawed, while others do not care or even appreciate a touch of Brett character. If you discern a peculiar taste, like an animal in bottle of old wine barrels, it is likely that smells Brett’s business card: a mixture of aromatic acid 4-ethylphenol, 4 vinylphenol, and Isovaleric that yeast Grape Products derived compounds.
6. Acetobacter – this genre is the poster child winemaking acetic acid bacteria. Analogous to lactic, acetic acid bacteria gain their name by producing large amounts of acetic acid. Acetic acid is familiar to us all, we buy it in bottles with the label. “Vinegar” In the world of wine, acetic acid is best known as volatile acidity, or simply “VA” addition of acetic acid, Acetobacter rid of acetaldehyde, which is described as having an “apple beaten, aroma and ethyl acetate, which helps the famous” nail polish remover “smell. Obviously, nobody wants most of these in their wines. The good news is that Acetobacter are obligate aerobes: they need lots of oxygen to survive. Fill the barrels, the oxygen exposure limit, and Acetobacter is much less likely to be a problem.
7. Kloeckera / Hanseniaspora – yeast same two names. Kloeckera is one of the good citizens who are standing silently in the background, live your life without lifting a smell, and do not talk much, either good or bad. Kloeckera earns his place in the Hall of Fame of absolute numbers, most of these strains cover the surface of good grapes, a virgin at the time of harvest than anything else. When the most is fermented spontaneously, Kloeckera survive and can contribute substantially to the early stages of fermentation. This yeast can be a major player in the rich aroma of the wine that started in a spontaneous, slow, and cool.
8. Pediococcus – “I asked” is almost as interesting as “Brett”, but not nearly as famous. Their effects on wine are excessive diacetyl (a buttery flavor or butter), biogenic amines, aromatic dirty sock and, worst of all, “stickiness,” a grotesque disaster that occurs when viscous Pediococcus (or perhaps some other microbes ) create long polymers of sugar molecules, dextrans. Moreover, Pediococcus may have some redeeming qualities. On the one hand, Pediococcus is very important in the fermentation of vegetables such as cabbage. Bacteria have also been found in wines that are clearly not spoiled. Unsubstantiated rumors whisper desirable Pediococcus can even add “complexity” in these cases. Expect more attention in the future as more bacteria and crops more often.
9. Botrytis cinerea – Botrytis is a fungus that, despite his gray, diffuse, unpleasant, often known as thin “noble rot” of the great things you can do for the wine under ideal conditions. Botrytis infected grapes in cold and wet. If conditions remain cold and wet, other microorganisms in and the result is a sticky and smelly. If dry and sunny weather is still in place, however, the influence of other spoilage microorganisms is mild and the result is some of the world’s most popular wines: Sauternes, Tokaji, and trockenbeerenauslese. Botrytis What do to help change the grapes rotted on the liquid amber ambrosia is complex beyond this debate, but involves the dehydration of the grapes and therefore the concentration of sugars, the discharge of metabolites such as glycerol, and the production of an enzyme (laccase) that contributes to deep golden color of these wines.
10. Flor yeast – The group of film-forming yeasts that cover the surface of sherry (and sherry-type) are specific “races” or strains of Saccharomyces cerivisiae: beticus, montuliensis, cheresiensis and rouxii. These yeasts are converted into a layer known as a film, flower, or flower on the surface of wine left exposed to air incompletely filled barrels. The flower acts like living plastic wrap, protecting the wine from direct exposure to air. At the same time, yeasts metabolize ethanol in the wine they produce large amounts of acetaldehyde to concede that the only nutty, bruised apple quality wines from Jerez style. In Jerez, where sherry is a native of the flower usually develops spontaneously. Sherry-style outside the region can be inoculated with starter cultures, and some are even produced in a completely different with a “black flower” held steady air bubbles through the wine.