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When you first start to ferment your own foodstuffs there is always the question about what can be used for the various fermentations you want to try. It seems like there are always more things to ferment then there are containers so the question arises “Can I just use old plastic containers?”.
Plastic containers can be used for short term, low temperature fermentation. Use food grade plastic containers which are BPA free and discard any with interior scratches or other damage which could harbor unwanted bacteria and mold.
Plastic containers are used in a wide variety of fermentation applications from primary buckets for wine and beer making to plastic tubs for making greek yogurt. These containers are tough, can survive dropping and are light enough to make them easy to move.
They also have their drawbacks as well such as:
- Plastic is soft and easily damaged
- Not all plastic is food grade
- Plastic chemicals can leach into fermentations
- Plastic is porous
- Repetitively using one time plastic containers is not recommended
Plastic containers are tough
This is a great benefit of most plastic containers but is extra beneficial when considering food grade containers. Containers meant for holding liquid or semi-liquid foods are pliable and strong.
The long chain polymers which makeup the structure of a plastic container make them very strong for their size and weight. They are pliable and bounce back to their original shape when bumped or dropped. This makes them good for holding large amounts of liquid which is heavy and hard to manage.
Plastic containers are light
As compared to glass or ceramic containers plastic is very light. The material itself is lighter than glass or stone making a plastic container of the same size and thickness lighter than the comparable glass or stone container. This reduces the amount of weight of a full container. Something to think about when you have a small location for fermenting projects which need to be moved around.
As compared to glass or ceramic containers plastic is very light. Plastic is made up of very long and intertwined carbon chains which are held together with very strong chemical bonds. This makes them stronger for the amount of material which is used to make them.
Plastic containers will not shatter
Plastic is pliable and will bend when moved around. When put under pressure the container can burst but will not shatter into a thousand sharp little pieces which resemble shrapnel from a hand grenade. When dropped they can break by splitting down the side making a hole in the container.
Glass or ceramic on the other hand when dropped tend to shatter into several pieces some of which are very small and hard to see. Each piece has sharp edges which can get into the skin. If a glass bottle bursts it can cause serious injury due to flying glass which can travel very long distances.
Plastic containers are cheap and are readily available
Plastic is the choice for bulk food transport. Buckets of all sizes can be found which hold anything from margarine (another form of plastic!), olives, potato salad and almost anything else which is semi-solid in nature. They are usually available for the asking from grocers, restaurants and wholesale distributors which break down large quantities into smaller saleable sizes.
They can be found in a variety of shapes from square, round, barrel shaped, wide mouthed or small mouthed and usually have a replaceable lid which can be reused a few times without worry.
Plastic is soft and easily damaged
Although the container itself is strong and resistant to breakage it can be damaged easily by a sharp object. This includes metal utensils, sharp rocks, seed pits or even hard sharp plastic objects.
When a plastic container is scratched it makes a long grove which can hold food particles, moisture and dirt. Once these are exposed to the air they can easily get infected with unwanted bacteria and mold. This can cause at best off flavors in the fermentation and at worst serious illness.
Not all plastic is food grade
Plastic comes in a wide variety of types which all can look the same even though their chemical makeup is different. Buckets which hold construction materials can look and act like food grade buckets but are dangerous to use to store food in the long term.
Another consideration is that most plastic bottles are not meant for reuse. Plastic pop bottles, water bottles and plastic yogurt tubs are all designed for one time use before recycling (hopefully). To use them more than once they need to be thoroughly cleaned as they can have odd shapes which can harbor unwanted bacteria and mold.
Plastic does not taste good
It is true that fermented foods are sold in plastic containers but they are only put into the container once the fermentation process is complete. They are then kept in a cool dark location for only a short period of time. Fermentations such as soy sauce or balsamic vinegar which can be aged for a long time are not placed into plastic containers until they are bottled for sale.
Other products like olives, sauerkraut and pickles are also fermented in large vats commercially until they are transferred into smaller containers which may include plastic pails or customer sized jars. Their exposure to the plastic is kept to a minimum due to the flavor transfer of new plastic products.
Plastic is not impenetrable and the plastic molecule is subject to damage and breakdown when exposed to light, heat and acidic or basic chemicals. This can impart unwanted flavors in a fermentation which cannot be removed.
There is lots of debate as to the source of such flavors which include:
micro-particles
Micro-particles can come from the manufacturing process and the chemical breakdown of the plastic itself. Nothing is completely stable and this includes plastic. It is damaged from agitation, scraping action and chemical processes.
Each of these break off tiny particles of plastic which get included in the fermentation which is being fermented in it. Depending on the length of time the food is kept in the container, how much agitation it gets and the age of the plastic will determine how much plastic is included in the food.
Plastic microparticles are becoming a serious environmental problem. The plastic molecule itself is difficult to break down and few organisms have the ability to use the long carbon chains for energy so they build up in the environment which can be dangerous to wildlife and human health.
Chemical break down
As mentioned above most fermentations sold commercially are not made in plastic containers but rather in large vats made of stainless steel, glass, ceramic or wood. Once the active fermentation is complete they are put in salable containers which could include plastic.
When plastic is exposed to heat, light and acidic conditions they release chemicals which are detrimental to health. It has been found that plastic containers put under normal use stresses leach estrogenic chemicals into the liquid it holds.
This is a hotly debated topic with lots of money supporting the use of plastic containers for storage and transport of food but anyone who has left a water bottle in the sun for a few hours knows the water will take on a plastic flavor. This flavor can have only one source, the container itself.
Active fermentations create agitation, heat and acidic reactions which also react with the plastic container. The plastic flavor will depend on the type of fermentation and the length of time it is exposed to the plastic.
Plastic is porous
Although plastic seems to be impenetrable it is actually quite porous. In fact it took quite a long time for manufacturers to produce a plastic bottle which could hold carbon dioxide long term. T
This is why plastic containers can get stained beyond the point of cleaning. The color containing liquid has seeped into the plastic and stained it. This makes it hard to clean properly, holding previous chemicals in its structure.
This means that the history of the container is very important when using reused or scavenged containers. Containers which were used to hold caustic or poisonous chemicals should not be used. Without a complete history of the container you cannot be certain that it has only been used for its intended purpose.
Repetitively using one time plastic containers is not recommended
Plastic food containers can be found in a variety of places. You can find them free from grocers, from purchased processed foods you have finished and you can purchase them new for a special purpose. Reusing one time plastic containers can lead to unhealthy or unsatisfactory results.
One time use containers can be difficult to clean, breakdown quickly or transfer flavors from previous foods which were stored in them. To safely use these types of container wash them thoroughly, ferment similar foods they previously contained and discard containers with stains or interior damage.