Fermentation
- Jodie Lindsay Popma
- Mar 30
- 7 min read
Pop-Up Workshop with Darragh Bryne of Craugh Catering, Feb. 22, 2025
What is Fermentation?
Fermentation is the process by which food substances are broken down by the enzymes produced by microorganisms such as bacteria, yeasts and fungi.
Humans have been fermenting food products for thousands of years through both trial and error and traditional techniques passed on intergenerationally.
Modern science has helped us to identify the exact agents of fermentation and the conditions necessary for successful and safe fermentation processes.
By understanding the agents responsible for a given style of fermentation and the conditions they require, you can prevent contamination by harmful pathogens and ensure the desired end product is created.
The Benefits of Fermentation
Probiotics: Fermented foods are rich in beneficial bacteria that support gut health and boost the immune system.
Digestibility: Fermentation breaks down complex nutrients, making them easier for our bodies to absorb.
Nutritional Enhancement: Fermentation can increase levels of vitamins and minerals, such as B vitamins and vitamin K2.
Preservation: Fermentation can extend the shelf life of foods, reducing food waste.
Flavor Development: Fermentation creates unique flavors and textures, adding complexity to dishes. Kokumi - richness and roundness that heightens the other five tastes and prolongs their flavour. It is found in both Eastern and Western cuisine where it naturally occurs in aged and fermented foods
Sustainability: Home fermentation encourages local food preservation, reducing reliance on processed foods. Fermentation is very helpful in creating closed loop food systems.
Team work is the best way to cook!
Introduction to Fermentation Workshop
In this workshop we will be looking at ways to incorporate fermentation into our daily lives and how we can start to create small closed loop food systems at home through fermentation’s many applications.
Fermentation can be both simple and complex depending on the type of culture required and the conditions it needs to successfully ferment.
For this workshop we will be looking at a simple form of fermentation known as Lacto-fermentation
Lacto-Fermentation
Lacto-fermentation occurs when lactic acid bacteria or lactobacillales convert the sugars in foods into lactic acid.
This results in a sour end product such as sauerkraut, sourdough, sour pickles or yoghurt.
These bacteria are salt and acid tolerant and are anaerobic, meaning that they thrive without the presence of oxygen. This makes it easy for us to create the conditions that will allow the lactic acid bacteria to flourish while deterring harmful pathogens from growing. (See next section of hand out)
Room temperature (Around 70F) will allow Lacto-fermentation to take place making it easy for us to do at home without the need of specialised temperature controlling equipment.
For this workshop we will be making sauerkraut and lacto-fermented root vegetables as well as sampling lacto-fermented blueberries.
Where can we find Lactic acid bacteria? - Everywhere! The benefit of Lacto-fermentation is that we do not need to purchase a starter culture. These bacteria are present on the surface of your hands, in the air and on the surfaces of the food you will ferment. The exact strain and pattern of these bacteria is unique to the hands of every individual. Therefore the ferments that you make by hand will have a unique flavor and texture every time you make it.
Safe Lacto-Fermentation Conditions
Firstly we need to wash our hands and sanitise the surfaces we will work on, the equipment we will use and the storage vessels for our ferments.
We do not want to completely sterilise our surfaces as the bacteria required for lacto-fermentation is present on these surfaces already and we do not want to kill them too. Running equipment through the dishwasher and then wiping them regularly with a sanitising solution such as food safe sanitiser or distilled white vinegar will be enough to deter harmful pathogens while allowing the lactic acid bacteria to survive.
It is generally better not to wear gloves for this type of fermentation as we want to encourage the lactic acid bacteria on our hands to aid the fermentation process.
Similarly when we wash our fruits or vegetables we want to wash off any dirt under cold water but we do not want to completely remove the lactic acid bacteria from their surfaces.
In order to further deter harmful pathogens, we will create a saline solution for our food. For our sauerkraut we will massage our cabbage with salt until water is released creating a saltwater solution to submerge the cabbage in. For our root vegetables we will create a cold saltwater brine in advance. It is very important that all of our food is completely submerged in the salt solution to prevent the growth of pathogens.
It is also important to create an airtight anaerobic environment to prevent aerobic pathogens from growing.
If you are worried that a ferment you have prepared has been contaminated or has begun to rot then compost it. It is better to compost it than become ill from consuming harmful microorganisms.
Experimenting
Once you have mastered the basics of both dry rubbing and brining foods for lacto-fermentation then you can start to experiment with both the foods you ferment and the seasonings you add.
Generally foods that have a higher sugar content will ferment more easily as the lactic acid bacteria convert sugar into lactic acid. Although adding salt to fruits may sound odd, the end product such as our fermented blueberries are delicious and complex and can be used in both savoury and sweet dishes. Berries are also a good example of a highly perishable food that can be preserved through fermentation, preventing unnecessary waste.
Starting a closed loop food system through fermentation
As well as experimenting with flavors, you can also begin to create interesting sustainable food systems utilising fermentation.
Any vegetable or food scraps that may not have a useful cooking application could potentially be fermented and repurposed for little or no cost.
For example, you notice that all you have in your refrigerator is a stick of butter, a pint of milk about to turn sour and a box of overripe fruits that you haven't gotten through from your CSA collection. You could lacto-ferment your fruitd and add a little vinegar to your milk to create some buttermilk. Now you can plan to bake some scones and turn your lacto-fermented fruits into a delicious salted peach jam to top them with. Lacto-fermented fruits can slo be dehydrated into delicious fruit snacks that also have a long shelf life
Many restaurants, homesteads and households will also can and ferment surplus produce during harvest time to be consumed during the off season or during winter when micronutrients may become more scarce.
How long should I ferment for?
Generally most Lacto-fermented products will need at least 3 days minimum at room temperature to produce a fermented product but fermentation could be continued for weeks or months depending on both the product and your preference.
Please note that the longer you allow something to ferment the more acid will be produced and the more the starch and sugar in the food will be broken down resulting in a more sour and mushier end product.
Adding foods with Tannin to your ferment can help keep the produce crunchy. Try adding grape leaves, bay leaves or tea leaves to your jar to both season your ferments and help maintain crunchiness.
A good place to start is five days to a week to test out your ferment.
One by-product of fermentation is Gas - usually in the form of co2. Because your ferment will be in an airtight container it is important to Burp your ferment every few days. This means slowly releasing some of the co2 from the container without fully opening the container. If you do not do this then you risk the container exploding or the lid popping off prematurely, exposing the ferment to oxygen and pathogens.
What should I do after fermentation?
Once you have opened your ferment and are happy with the level of fermentation then you want to slow down the fermentation process by putting the ferment in the refrigerator.
Once the ferment is exposed to air and is no longer being held anaerobically, please treat it like any other perishable good and consume within a few days.
Remember to try and utilise the ferment further. Fermented foods taste great when cooked such as kimchi fried rice or a grilled sauerkraut reuben sandwich and they can also be utilised in a process known as Backslopping.
Backslopping
The juice from a previous ferment can be used to kickstart a new fermentation process. Using the culture formed from one ferment to start a new ferment is known as backslopping. This is more important for processes such as kombucha making but can help in lacto-fermentation too.
Backslopping can also be used to create interesting fermented products such as nut cheeses or non-dairy yoghurts too. (See recipe for pumpkin seed cheese below) this can also be another useful tool to utilise food products that might go to waste otherwise.
Factors to Remember
If you are having trouble remembering what you need to do or if your ferments are not turning out then please refer to these factors to ensure you have created the right conditions for your fermentation process
Washed hands and sanitised workstation, equipment and storage vessel to prevent the growth of harmful pathogens
Do not sterilise your equipment with heavy chemicals or wear gloves - you don't want to also kill the lactic acid bacteria required for the fermentation process. Use distilled vinegar or food safe sanitiser.
Make sure your food product is completely submerged in the salt water produced for the fermentation process and weighed down by a weight or rock to keep it submerged, this will deter pathogens that can’t tolerate salt
Make sure the vessel you are using is sealed airtight in order to create anaerobic conditions which will also deter pathogens which require oxygen to grow.
Ensure that the ferment is held at Room Temperature or slightly higher to allow the lactic acid bacteria to flourish.
Check your ferment and Burp the jar or vessel every few days to prevent the jar leaking or exploding.
Let fermentation take place for at least three days before it is ready to eat.
Store opened ferments in the fridge to prevent it from spoiling once exposed to oxygen.
If your ferment smells rotten or is discolored or moldy then Compost it. If you doubt it is safe to eat then do not eat it.
The Longer you Ferment the more sour and mushier it will be. Adding tannin rich foods to the jar can help maintain crunchiness.
February 22, 2025, Darragh Byrne - Cruagh Catering Co.
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