Some people don’t correlate the relationship between sugar, yeast and alcohol.
In Australia the only legal permissable use of cane sugar in wine is for “dosage” in Methode Champenoise or Sparkling Wines. (This is one reason Sparkling Wines have more calories ladies…). Thus, the only legal way (in Australia) to get sugar in your fruit (grapes) is to make sure they ripen – natural sugars are glucose and fructose.
We are allowed to add alternate means of acid and tannin as well as preservative. This is a good thing:
Consider some other kind of fruit growing in your back yard. If you picked a tomato when it was green, there is a higher amount of acid than there is sugar. The longer you leave it on the vine, the more this balance sways the opposite way – less acid to higher sugar.
Same thing goes for grape vines, we need more sugar in our grapes than acid for the average wine. Keeping in mind this is natural sugars that build up through photosynthesis in the grape vine. (Sunlight + leaves = ripe fruit) But if we harvest too ripe, we can then back up the balance with extra acid/ tannin. If we harvest too early its going to taste tart and acidic and will probably have to be used for Sparkling Wines.
Why is all this important? What I am about to demonstrate is a science lesson.
In order to make wine, we use the basic principal called fermentation. Fermentation works like this:
Sugar +Yeast = Carbon dioxide + Alcohol
Yeast can naturally be found on the skin of the grape, so traditionally none needs to be added. However, as later described, “super” yeasts have been grown in order to be more resistant as well as consistent. Yeast will also affect the flavour.
Yeast is a living thing. Consider this: “Yeast Man”
“Yeast Man” eats sugar, and through this process, Alcohol and Carbon Dioxide are released. This is why wine is alcoholic, and also why Champagne has bubbles. (More on this another day).
But “Yeast Man’s” Kryptonite is: eating and shitting in the same place. Hes a greedy little bugger and creates a sort of toxicity that even he can’t survive. Yeasts will keep going through this fermentation process until:
- He runs out of sugar
- The temperature gets too high and he dies
- The temperature gets too low and he goes to sleep
- Too much alcohol takes over in the early stages of the wine and he drowns in his own piss
The amount of sugar in the fruit will depend on the amount of alcohol in the wine – unless the yeast is killed and residual sugar is left over. This often produces a fruity or sweet wine.
Some yeasts are more resistant than others but on the most part – too much alcohol or the wrong temperature will kill a normal yeast. This is when “Yeast Man” gets a makeover and they reinvent him as a da da da da…. SUPER YEAST MAN!
Super Yeast Man laughs in the face of danger. (Well not really, but they can build yeasts that don’t die so easily).
But it has not been identified whether Super Yeast Man’s Clark Kent is named Brett (after Brettanomyces) or Lee (as Lees is the name given to dead yeast cells).
So now you understand (or are even more confused than before) about Yeast and Fermentation, take a moment to consider all the living yeast cells that had to die for your glass of wine. Casualties of consumption.
Cheers!
