Eating fermented food is not a new idea. Fermentation is actually the oldest method of food preservation we know about and evidence has shown that it has been used for more than 7000 years. We regularly drink wine and beer that has been fermented, but most people are largely unaware of the benefits of fermented food.
Fermentation is also employed in the production of other common foods. The action of yeast in producing carbon dioxide which causes our bread to rise is one example of fermentation and another is the use of vinegar (acetic acid), a product of fermentation, to pickle various vegetables and other foods.
Over the last century, humans have been engaged in a war against microorganisms. Although some of these have been shown to be dangerous and cause disease, many are actually beneficial. In recent years we have begun to realise again that, in addition to their role in preserving food and keeping it safe to eat, beneficial microorganisms help our digestion and provide substantial health benefits.
The process of fermentation uses natural ingredients to encourage growth of these beneficial microorganisms, or probiotics as they are commonly known. They help to restore the correct balance of bacteria in the gut.
Many conditions such as lactose and gluten intolerance, asthma, irritable bowel syndrome, constipation and allergies are believed to be linked to an imbalance of bacteria in the gut.
Fermenting food is like partially digesting it before we eat it. This is why some people can tolerate yoghurt but not milk - the lactose in milk is broken down as the milk ferments and turns into yogurt.
Fermented foods contain increased levels of folic acid, which is very important for pregnant women in preventing birth defects, along with various other vitamins including the B vitamins. They are also rich in enzymes, which are needed for digestion and absorption of food.
Fermenting food means that it will keep safely for longer. Yoghurt will last longer than milk in the fridge for this reason and sauerkraut, salsa and pickles will keep for a long time.
Fermentation can increase the flavour of food. Many fermented foods such as smelly cheese, salsa and sauerkraut are particularly enjoyed because of their strong flavours.
There are increasingly more raw fermented foods available commercially, from kombucha which is a slightly sparkling fruit or vegetable drink made from raw ingredients and rich in probiotics to unpasteurized hot sauces also made by lacto-fermentation.
At home, it is easy to make healthy sourdough bread. First you need to make a starter with a paste of bread flour and water. The starter should be left in a bowl covered with a damp tea towel and will need "feeding" over the next few days until it is ready to use. A sourdough starter uses yeasts that are present on flour and found naturally in the atmosphere. It can last for many years and can be shared with family and friends. Every time you make bread, you will have some starter left over. If you keep this in the fridge and feed it every 4 days it will improve in flavour.