EQUIPMENT

Equipment for Making Sauerkraut and Pickles

Making sauerkraut and pickles requires very simple equipment such as kitchen knife, food grade plastic bucket, a clay jar and wooden weight. There is also a variety of professionally made sauerkraut fermentation crocks made from baked clay such as the German Harsch or Polish fermentation crocks.

Knife

If you plan on making enough sauerkraut to just meet your own or a small family's needs, you can slice cabbage with a kitchen knife, just make your cuts 1/16-1/8" thin. Keep in mind that the cabbage has to be cored and is normally cut into quarters, even if a mandoline slicer is employed. In some cases, for example when shredding Chinese soft textured cabbage, the knife is the most practical tool.

Cabbage Slicer

There is a variety of small mandoline slicers, general purpose slicers, and other gadgets available on the Internet that will shred cabbage and other vegetables very well.

Cabbage has to be cored and is normally cut into quarters, even if mandoline slicer is employed. A quarter of the cabbage rests firmly on its flat side and you can easily shred the other flat side with a knife. And if you slice cabbage into 1/16", 3/16" or 1/8" slices who cares? It will still ferment and your sauerkraut will be just fine.

Four fingers on the cabbage, thumb behind the sliding box and the cabbage is shredded in a few moves. In order not to cut your fingers you have to stop shredding when little cabbage still remains. A new cabbage quarter is placed on those remaining leaves and the operation continues.

Fermentation Containers

The process of making sauerkraut is very forgiving as sauerkraut is one of those great foods that needs very little help on our part and it always turns out great. There is a variety of containers will do a nice job. Fermented containers should not be made from regular metals (stainless steel is the exception), as the fermentation produces lactic and acetic acid, which will react with metal.

Food grade plastic buckets make wonderful fermenting crocks. If you are not sure of the origin of the bucket, you may line it up with a plastic cooking bag. There are general purpose and turkey roasting plastic bags available.

Fermenting Glass Jar

Fermenting glass jars with the air-lock installed in the lid are inexpensive and available on the Internet, bur you can make your own even cheaper using basic skills and tools. In open containers a periodic inspection is needed to check for odors and to remove any slime. This requires washing weights, scooping up the slime, discarding bad top leaves or washing/replacing top cloth. With the water channel container those chores are eliminated providing that the water level in the channel is maintained. This requires adding water every few days, depending on the ambient temperature and humidity. There is nothing to add or maintain when a glass jar with an air lock is employed. The water will remain in its small diameter tube for months.

A simple yet practical version of a fermenting crock is a 1 gallon glass (or food grade plastic) jar that has a double bubble air lock attached to the lid. This is the same set up that is used for making wine. Shredded cabbage is tightly packed, weighted and the lid is twisted on. When cabbage is fermenting the bubbles are travelling through the air-lock.

After a while there is no air available to any yeasts or molds that might be inside and there is no white scum on top of the product. The lid is not removed during fermentation and when the bubbles stop, the fermentation is completed.

Professionally made glass jars with the air-lock installed in the lid are inexpensive and available on the Internet.

The advantage of the glass fermenting jar are many:

Its transparency. The fermenting process can be seen all the time.

The cost. The jar costs just a fraction of the clay fermenting crocks.

Size and weight. Clay crocks are huge and heavy.

If someone intends to process 50 pounds of cabbage, the cost of a large and very expensive clay crock is justified, but for processing 10 pounds of cabbage the glass jar is a clear choice. The weakness of the jar is its fragility, the second inconvenience is that during fermentation it should be covered with a dark plastic bag or kept in a dark room.

Fermenting Clay Crocks

Fermenting clay crocks and glass fermenting jars are based on the same principle that has been used for centuries to ferment wine. In both cases the water separates the contents of the container from the outside air.

The principle is based on water separating the inside of the vessel from the outside air. It has been used for centuries in wine fermentation where a simple, inexpensive tube of glass known as an "air lock" performed the trick.

Water channel clay fermenting crock is a maintenance free device as long as the water is present in a channel. This crock produces a top quality product. Water of course evaporates, so it must be added when needed.

Lactic acid bacteria break sugar into lactic acid and produce CO2 gas. As the gas volume increases it produces higher pressure inside of a crock. The expanding CO2 gas pushes out any air that resides above sauerkraut. A mixture of air and CO2 (soda gas) is pushed through the water channel. After a while there is no more air present and only gas escapes away. The absence of air prevents yeasts from growing and becoming slime on the surface. The vessel is pressurized and the lower pressure outside air can not enter the crock through the water channel. Even when the fermentation stops, the outside air cannot enter the fermenting crock. Of course removing the lid equalizes the pressure on both sides, but if the fermentation is still ongoing, this air will be pushed out again. For those reasons the lid should be removed as little as possible during fermentation.

Make note that CO2 (soda gas, carbon dioxide) is heavier than air. After a while there will be a layer of CO2 on top of sauerkraut, further protecting it from the air. If, for any reason, you need to remove the cover and inspect the sauerkraut do it carefully. Don't mix or stir sauerkraut as this will damage the CO2 layer and will introduce air into the sauerkraut.

Polish Boleslawice crock on the left, German Harsch on the right. The crocks come in sizes from 5-50 liters (1.3-13.25 gal)

The main advantage of German Harsh crock and Polish fermenting crocks is that the water channel creates a barrier between product and the outside air. Carbon dioxide gas (soda gas) is created during fermentation and it pressurizes the inside of the crock. Carbon dioxide and air escape from the crock through the water channel. The outside air is at the lower pressure and cannot get inside the crock. As the result there is no air available to any yeasts or molds that might be inside and there is no white foam on top of the product. The lid is not removed during fermentation and only water is periodically added to the water channel. We have kept sauerkraut undisturbed for 3 months after fermentation stopped and the quality was superb. If a crock is left unattended for long time and all channel water evaporates away, the advantage of the design is gone as the outside air will sip in. Clay fermented crocks come with split clay weights.

Fido Jar

Fido jar is a glass storage container with large opening. Lid is closed down with a metal clamp and vulcanized rubber provides an airtight seal. Those jars were always popular in Europe and were used for canning and storing foods. A good fermenting container is able to release air and pressurized carbon dioxide to the outside and prevent the outside air from coming in. A water channel clay crock or glass jar can do it easily. Sauerkraut made in the least expensive jars is as good as the one made in the most expensive ones or fermenting clay crocks.

It is all about keeping out the oxygen.

Many people swear that Fido is the best jar for fermenting, so let’s see if this is the case.

Fido jar is a storage jar. It is capable of fermenting cabbage (any container is), however, it has some shortcomings. The locking pressure of its clamp varies from jar to jar. Ideally, the expanding gas should push out the air through the rubber gasket, but what happens if the clam locked the lid very strong?

Lactic acid bacteria will keep on producing more and more carbon dioxide (CO2, soda gas) which will expand in volume. The rubber gasket will be pressed by the locking clamp so much that the gas and the air will not be able to escape. The air will be forced to remain inside and the molds may start to grow. A lot will depend on whether the cabbage is fully submerged in brine, and how much air and molds are available. If glass jar if of a large size, the glass may crack under pressure.

This will never happen in a fermenting crock or a glass jar which are under constant pressure of the outside air. This is the maximum pressure that presses down on water in a channel or in the air lock. The air lock could become clogged with food if the jar was overfilled; but the gas pressure will push out the rubber grommet.

It is hard to predict how much pressure locking clamp applies to the vulcanized rubber washer. Some Fido jars are beautiful and expensive, others are cheap imports with easily breaking clamp. So, to make the story short, Fido jar can be used for fermentation, however, its operation is not as predictable as that of a fermenting jar with air lock. Adding a little oil may be a good idea as the thin layer of oil on top of the brine will keep away any air that may be present.

Fermenting glass jars should be kept in a dark place.

Weights

The type of weight is of little importance what is important is that sauerkraut or pickles should be submerged in brine in order to create a barrier between the product and the air above. This prevents yeasts and mold from going on top of the product. Originally wooden covers were placed on top of the fermenting product and the additional weight was placed on the cover. Rocks, bricks or large gravel are often placed directly on top of the whole leaves.

Weight gravel.

Weight plate. In many jars and crocks the mouth of the container is narrower than its body and a split weight plate must be used.

Small fermenting glass jar. An inverted dinner plate makes a great cover and additional weight is placed on it. That could be a plastic bag filled with brine or a glass jar filled with similar strength of a brine.

There are two types of airlocks:

S-types. The pressure differential is more apparent with an S-type airlock so it is easier and faster to notice fermenting activity. This may be more important for someone brewing beer or wine.

3-piece round type. This type is about 2" shorter and much easier to clean.

Both airlocks are manufactured differently: the 3-piece is perfectly round, you may get a S-type that is slightly flat instead of round and won't seal well in the stopper. We use both types and never had an issue. We generally use the S-type for making wine and 3-piece for fermenting vegetables.

The airlock is an absolutely wonderful device. It has been instrumental in making wine for centuries. It is made from plastic, costs about one dollar and it works perfectly. An airlock is a small amount of water that physically separates the inside of a fermenting vessel from the outside air. The air creates problems during fermentation as it promotes mold development. Decomposing cabbage contains nutrients and water that bacteria and molds consume, but molds need the air to survive. Cut off the air supply and you will kill the molds. Kill the molds and the sauerkraut will be perfect every time.

Air-lock Principle

Round air lock, fermentation in progress.

The principle remains the same as for S-type air lock or the water channel. Water separates contents of the jar from the outside air. A little cap does the trick; accumulating pressure lifts up the cam and the gas escapes to the outside. There is a little plastic cover with tiny holes on top to prevent insects from getting in.

Operation of an S-type airlock.

Drawing A - There is no fermentation taking place when freshly cut sauerkraut or fruit are placed inside of a crock. The pressure inside the crock equals the pressure on the outside of the vessel. We have an equilibrium state. This is demonstrated by the same water level on both sides of the U-tube, which in our case is a part of the air-lock.

Drawing B - Bacteria need some time, usually a few hours to spring into action. They break sugar into lactic acid and produce CO2 gas. As the gas volume increases it produces higher pressure inside of a crock. This expanding gas travels up the tube and pushes the water level up as can be seen in a U-tube. The beauty of design lies in the fact that the expanding CO2 gas pushes out any air that resides above sauerkraut. Thus, the raising bubbles which can be seen in the U-tube are a mixture of air and CO2, which is a soda gas. After a while there is no more air present and only gas escapes away. The absence of air prevents yeasts from growing and becoming slime on the surface. The vessel is pressurized and the lower pressure outside air can not enter the air-lock and the crock. Even when the fermentation stops, the outside air can not travel through the water in the air-lock. Of course removing the lid equalizes the pressure on both sides, but if the fermentation is still ongoing, this air will be pushed out again. For those reasons the lid should be removed as little as possible during fermentation.