This word describes a process by which living things break down carbohydrates to make other molecules and provide energy to cells or organs. Carbohydrates are common compounds in food and include sugars and starches Some microbes use fermentation to get energy from carbohydrates. When people put those microbes to work, this process helps make both food and fuels.
Fermentation makes acids, alcohols, gases and other chemicals. A microbe called yeast, for example, ferments the sugars in bread dough. This makes the gas carbon dioxide. Bubbles of that gas make a loaf of bread rise and become light and fluffy. Yeast also make the alcohol in wine and beer.
People can use fermentation to make alcohol for fuels. For instance, bacteria and yeast can break down sugars and starches from plants, such as corn. That fuel can be added to gasoline to help power cars.
The microbes in animal guts, including in our own guts, ferment. When cows digest grass, some of their gut microbes make methane gas. That gas escapes when they belch or fart. That might sound funny, but methane is a greenhouse gas. It traps heat and contributes to global warming.
Fermentation isn’t just for microbes. Our muscles can also ferment. Animal muscles usually get energy from a process that uses oxygen. When they can’t get enough oxygen, they use fermentation. That’s because fermentation doesn’t require oxygen.
STEP ONE
In a big bucket with 3lb raspberries (you can choose your own fruit, almost any will do), Pour on 5pts of water and added a teaspoonful of pectin enzyme to prevent ‘pectin haze’. Then mash berries with a wooden spoon and covered the liquid with a tea towel (very important esp. in summer to keep insects out).
This is left for two days.
STEP TWO 2 DAYS LATER
Add to the bucket between 1kg and 11/4 kg of sugar (preferably fair trade/organic, white) dissolved in 2 pts water off the boil. Add 1 tsp dried yeast with a little sugar all dissolved in some of the fruit liquid in the bucket.
It’s the yeast that turns the sugar into alcohol and the more sugar the sweeter the wine. Nick uses less (1kg) as he likes a drier wine.
This liquid is then stirred 2-3 times a day over the next four days, and the process is called ‘fermenting on the must’.
STEP THREE 4 DAYS LATER
This is the messy bit, where you strain all the liquid through a muslin sieve, before funnelling it into the demi-johns and putting an airlock on it. This is then left to ferment for between 3 and 18 months until there are no longer any bubbles to be seen in the airlock. During the fermenting process a stable temperature is important. Nick doesn’t worry too much about whether it’s warm or cool, just that there is as little fluctuation as possible.
STEP FOUR 3-18 MONTHS later
Decant into bottles and leave for 1-2 years depending on the fruit. Raspberries need less time than elderberries, for example.
Now invite everyone to taste some of the wine made – for medicinal purposes only, of course.