While my blog (and neglected Youtube channel) has focused on alcoholic fermentation, I don’t think it would surprise my readers/viewers to learn that this is not the only kind of fermentation I am interested in. Like many homebrewers, what started off as a way to get cheap beer quickly evolved into a way to get good beer…and from there transformed my life (and kitchen) into an unending quest to make and try new fermented foods and beverages.
I cannot offer a reason as to why I haven’t blogged about fermented foods before – they are as much a part of my life as is beer brewing. It is a rare day someone comes by our home and there isn’t a vat of yoghurt, sauerkraut, pepper sauce, pickles, cheese, sausage, kimchi, kombucha, sourdough, ginger beer, eggs, or vinegar fermenting away. And, like many homebrewers, there are a range of foods in which my homebrew is a feature ingredient, or foods which I love to indulge in alongside a pint or two. Fermented (and beer-inspired) foods offer a wonderful opportunity to explore your local terroir – both in the character imparted by your environment on foods grown at home, and the flavours imparted by your local microbes as they ferment these foods.
As you may have guessed, I am now going to start incorporating some of this material into my blog – focusing on the science, microbiology and art of food fermentation.
Where to Start
Like learning to brew beer, starting to make your own fermented foods can be somewhat daunting. Many of the instructions found in books and the web can be vague. Making matters worse, fermented foods attract a lot of peudoscientific nonsense and post-modernist fervor that can lead you astray. One of the major goals of this new blog series is to cut through this noise by providing detailed, science-based discussions of fermented foods, their microbiology, alongside easy-to-follow recipes to get you started. In addition, I’ll do my best to point you towards other quality resources.
But don’t worry – as a brewer of beer, you have learned many of the skills required for the safe and successful production of fermented foods. Moreover, you have already acquired a lot of the equipment and knowledge you need to get started. If you have an old pickle jar and an airlock, you’re pretty much ready to go!
As with beer brewing, the fermented food hobbyist has a world of gizmos, whatchamacallits, thingamajigs and doohickies they can buy to further their hobby. And like with homebrewing, there is all sorts of things that the gear heads can make themselves, super-power, and over-engineer. And just like homebrewing, all of that is superfluous and you can get away with stuff literally pulled from the rubbish bin.
When making (most) fermented foods you only need four pieces of equipment:
- An acid/salt resistant, food-safe container.
- An airlock or other way of minimising the amount of air (oxygen) that gets into the container. There are exceptions to this – notably,cheese, vinegar and kombucha all need some degree of air exposure. But for most fermented foods air is verboten.
- A kitchen scale with a resolution of ~0.5 gram/0.1 oz.
- A measuring cup
General Considerations: There are three main things you need to consider when selecting a fermentation container:
- The container needs to be food-safe. Reusing a food container (e.g. glass pickle jar) is a good place to start; likewise, containers intended for home canning (glass or ceramic canning jars) are also a good choice.
- The container needs to be non-reactive to salt and acid. Glass, plastics and ceramics all fit this criteria. Generally you want to avoid metals – even stainless steel or enamelled containers – as these will often corrode or leach metals when exposed to acids.
- You need an material that is oxygen impermanent – i.e. oxygen cannot penetrate the material. Glazed ceramics and glass excel at this. Thick plastic containers also do the trick, but thinner plastics should be avoided.
For practical reasons, plastics are generally a poor choice. They cannot be sanitised by boiling, and if scratched, can be hard to sanitise with chemical sanitisors. In addition, they can transfer flavours from one batch to the next. As such I generally recommend that they should be avoided – but they can work in a pinch.
The Budget System:
The cheapest entry point, equipment wise, is to use reuse a glass food container (e.g. pickle jar) as your fermenter and a zipper-seal bag as an airlock. Yes, as in a $0.05 bag and a “free” jar. Sanitise the jar (more on this below), fill it to just below the neck with the food to be fermented (more on this in future posts), and then place a sanitised plastic bag on top of the food. Fill the bag with water – it should expand and tightly seal around the circumference of the jar – and you’re good to go. Adding a few stainless steel ball bearings or glass marbles to the bag can help keep it in place.
While cheap, this system has many issues. Brine tends to push its way up past the side of the bag, allowing mould to grow around the lip of the jar, and occasionally running down the side and making a mess. The mould isn’t an issue – just wipe it off – but it can be unsightly. The bigger issue is the mess, which can get smelly if you don’t notice it right away. I’ve also found this system tends to attract fruit flies. So while its a good way to give fermented foods a try, I’d not recommend it once you’ve decided to stick with the hobby.
The “Homebrew” System:
As a beer brewer you likely have a few airlocks in your possession. This puts a slightly better (but still “free”) setup within your reach. All you need is a food-grade jar with a solid metal lid. Do not use a 2-piece lid like those on a mason jar, as its hard to get a good seal. Drill a hole in the centre of the lid just large enough to fit the airlock, and insert the lock. For a better seal, use a small amount of food-grade silicone or wax can to seal the lock to the lid. You can also buy commercial setups that are built this way.
I brewed with this setup for over a decade. They are cheap, reliable, easy to make, and don’t suffer many leaks. They do have their limitations. The main issues I’ve encountered all have to do with the use of a water-lock. And they are the same issues beer brewers encounter with these locks. A vigorous fermentation can push brine into the airlock, leading to a mess and the potential for contamination. Changes in temperature can result in suckback, pulling the liquid from the airlock into the food. This can contaminate the food with nasty airlock liquid, and leave the food exposed to air. Finally, with longer-fermenting foods, there is also the risk of the airlock running dry. Again, this exposes the food to air, which will lead it to spoil. These are easily manageable issues, but they are issues to be aware of if you go this route.
The “Cadillac” System:
Recently I upgraded my fermentation system to waterless airlocks, which resolve the issues associated with water-locks. There are a lot of variations of these systems, with a corresponding range in quality and cost. Quality systems are typically available for $10-12/lock (in Canada, in the USA these appear to run $8-$10 for the same products). These airlocks do not suffer from suckback issues, nor can they run dry. They are not impervious to vigorous fermentations pushing brine into the lock. But they are much easier to clean, and most will maintain their seal after an overflow.
Some systems, like the one I purchased, come with a simple pump that allow you to pull a slight vacuum. This is a great way to limit oxygen exposure for more delicate foods, and to degas a food prior or during fermentation. There are many variations of this system, but I chose fermentation lids that fit a standard wide-mouth mason/canning jar. I prefer this system as it offers many advantages:
- Glass mason jars are completely impermeable to air.
- The jars are common, easy to find, cheap, and of quality construction.
- The lid fits any large-mouthed jars, allowing for the same airlocks to be used for fermentations ranging from 250 ml (1 cup) through to 8 liters (~2 gallons) in volume.
- Once fermentation is complete, the jar used for fermentation can be sealed with a standard mason lid. Thus, separate containers are not needed for fermentation and storage/serving.
- If desired, the fermentation jar can be sealed and canned or pressure-cooked for long term storage.
- The jars can be sanitised by boiling.
Keeping Fermented Foods Submerged
Even with a good airlock, many fermentations will still need “help” keeping the food below the level of the brine. This is especially true of foods such as fermented peppers and sauerkraut, which tend to develop unwanted bacterial growths or go mushy if they don’t stay completely submerged. Some people have luck just adding a bit of extra brine, but I’ve never been that lucky.
A cheap option is to use river stones as weights. They are free, but it can take a bit of effort to find and prepare a good stone. You want to find a stone that is disk-like in profile, with a diameter just a little smaller than the opening to your fermentation container. I.E. something that would make a good skipping-stone. Before using a store be certain you clean it well…and it may be a good idea to find someone familiar with minerals, to make sure the stone isn’t toxic.
If using a large container, a ceramic or porcelain kitchen plate works well as a weight. While I don’t ferment on that scale, I know many sauerkraut afficianos who ferment in large crocks and weigh down the karut with heavy plates.
The best option is to purchase fermentation weights. These are glass or ceramic weights, cut to fit the opening of your fermentation jar. There is no risk of anything leaching into your food, nor will flavours leach in/out the weights. These can be found fairly cheaply, and a keen shopper can often find cheap glassware that can be used in place of purpose-made weights.
As with fermentation vessels, plastic or metal weights should be avoided.
Cleaning and Sanitation
As with brewing, cleanliness is critical when making fermented foods. And as with brewing, the first step in preparing a fermented food is to clean all equipment that will contact the food, as well as the fermentation vessel and airlock system. Dishwashers are sufficient to clean all equipment, as is a sink of soapy water. In many cases this is all you need. But for infection-prone foods – e.g. fermented peppers, or anything made of milk – proper sanitation of your equipment is required. And to be frank, it takes a minimal effort to sanitise your equipment, making it a very cheap and simple way to limit the risk of ruining a batch regardless of how infection-prone the food is.
Many of the sanitation products meant for use in homebrewing will also work for fermented foods, especially products sold as no-rinse sanitisers. I recommend avoiding iodine-based sanitisers (e.g. iodophore), as iodine will harmlessly, but unattractively, stain the food. Another thing you should consider is that fermented foods are (generally) made in smaller volumes than beer. Meaning that proportionally speaking, if you don’t rinse, you will leave a larger quantity of sanitiser behind, relative to the volume of food. This increases the risk of your food taking on the flavour of the sanitiser, or of the sanitiser negatively affecting fermentation.
As such I prefer to use boiling to sanitise all glass, metal and ceramic components. I use StarSan to sanitise anything made of materials which cannot be boiled, or which are too big to fit in a pot. But even though it is a no-rinse sanitisor, I rinse these items off afterwards with tap water. If you cannot trust your tap water to be clean, use boiled water instead. I always sanitise the fermentation container, weights and airlock. If working with milk, meat or eggs, I also sanitise all tools and mixing containers that will contact the foods. I don’t bother with this extra sanitation for fermented vegetables or fruits, as the risk of contamination is much lower.
Coming Up Soon in the Fermented Foods Series
Watch my blog over the next few weeks for upcoming articles on fermented food microbiology, (properly) preparing brine, and recipes for fermented pepper sauce and sauerkraut…
…there may also be some beer-related posts coming up soon as well, as the new trailer for my Youtube channel subtly suggests.