When you first start brewing kombucha, it can feel like a complicated drink to make. There are so many rules about what to do and not to do, that it can feel overwhelming for someone new to the hobby.
Lucky for you, I’ve been brewing kombucha for a while now and while I’m no expert, I have done tons of research on home brewing techniques during the process of writing this blog.
Today I’ll be going over the common question new kombucha brewers have of whether or not you can use plastic to brew kombucha.
Plastic should not be used during the kombucha brewing process of 1st fermentation as the acidity in kombucha can rub off toxins and chemicals such as BPAs from the plastic into the kombucha. Plastic bottles can be used for 2nd fermentation, but won’t create as good of carbonation as quality glass fermenting bottles.
In this article I’ll quickly cover the basics of the kombucha brewing process before going into detail on why or why not and when or when not you should use plastic while making kombucha. Let's get started!
An Overview of the Kombucha Brewing Process
Before we talk about how kombucha and plastic interact, you need to understand the overall process of how kombucha is made. If you’ve already made kombucha before and are familiar with it, you can just skip ahead to the next section.
All kombucha begins as sweet tea. What turns this sweet tea into sweet and sour probiotic kombucha is a living culture of bacteria. This culture of bacteria, known as a SCOBY (Symbiotic Culture of Bacteria and Yeast), eats the sugar and caffeine from the sweet tea and produces acids, carbon dioxide, and alcohol.
Once it has eaten enough sugar to make the kombucha bitter tasting, the SCOBY is removed and the 1st fermentation is complete. At this point the kombucha can be drunk, but it's not carbonated or flavored yet.
The carbonation and flavor is added in a 2nd fermentation. During this stage, the kombucha is sealed in glass fermenting bottles that are filled with fruit, juice, or herbs for flavoring.
Over the course of a few days, the kombucha in the bottles develops carbonation and flavor. It’s then refrigerated and ready to be drunk by people like you and me!
Can I Use a Plastic Container for 1st Fermentation?
Can you brew kombucha in a plastic container during the first fermentation? Well you technically can, but ideally you shouldn’t.
The reason that it’s recommended you don’t brew your 1st fermentation of kombucha in a plastic container is because over time, the increasing acidity of the brewing kombucha can wear down the plastic material and release harmful chemicals such as BPAs into the kombucha
BPA is a chemical found in almost all plastics that in high doses may lead to cancer, heart problems, and disrupted hormone levels. Although there's still a lot of research that needs to be done around how BPAs affect our health.
But even if BPAs aren't harmful to your health, the chemicals corroded off of the plastic may still be dangerous to the living bacteria culture that ferments kombucha known as the SCOBY (Symbiotic Culture of Bacteria and Yeast)
The SCOBYs job is to eat the sugar and nutrients from the sweet tea that kombucha starts as and convert them into acids, alcohol and CO2 to make kombucha. But, the SCOBY is a hungry creature and will eat anything near it. So if dangerous chemicals corroded off the plastic are in the kombucha, it’s going to eat these things.
And because the SCOBY is super sensitive (even touching it with unwashed hands could hurt it) if it eats the chemicals from the plastic, it will become damaged, die, or weakened to the point that it can no longer fight off mold.
Another danger of using plastic to brew the 1st fermentation of your kombucha is that plastic, unlike glass or stainless steel, can get scratched. Especially after continual use.
The problem with scratches is that bad bacteria can develop unhindered in the crevices created by them, leaving your kombucha and SCOBY exposed to harmful bacteria and completely ruined.
Now while I am making this seem like a black and white answer. That kombucha can never ever be brewed in plastic. But the truth is, there are people that have and currently do brew their 1st fermentation of kombucha in plastic.
Certain plastics like PET (polyethylene terephthalate) and HDPE (high-density polyethylene) that are manufactured to be durable, strong, BPA free, and resistant to corrosion may work for kombucha brewing.
But just because you can do it, doesn’t mean you should. With how cheap glass jars are I don’t see how it’s worth it to use plastic for the 1st fermentation of your kombucha. All you’re doing is risking killing your SCOBY and damaging the health of you and anyone else who drinks the booch.
So if you can’t use plastic, what kind of container should you use for the 1st fermentation of kombucha?
What Container Should You Use for 1st Fermentation?
While you can use stainless steel, food grade porcelain, ceramic stoneware, or wood to brew your kombucha in, most kombucha home brewers, myself included, use glass jars to brew their kombucha.
Glass is a great material to use because it doesn’t have any of the toxins or BPAs in plastic. Plus it’s pretty cheap and easy to find. You can get a 1 gallon glass jar at almost any grocery store, or even online on amazon. Glass also allows you to see your brew as it develops and show it off to friends or family that visit.
Save a trip to the store by getting your glass kombucha jar on Amazon. This pack of two 1 gallon glass jars will allow you to get started brewing kombucha quickly and for a great price (it’s Amazon Prime Eligible). These are the jars I use and they work great. You can check them out on Amazon here.
Can I Use a Plastic Container for 2nd Fermentation?
While it’s a hard no on using plastic for your 1st fermentation, 2nd fermentation is a little more flexible.
Generally, glass is still the recommended material for 2nd fermentation. However, plastic bottles can be used for 2nd fermentation with a lot less risk than the 1st.
One reason you can use plastic bottles during 2nd fermentation is that the acidic kombucha is in them for a lot less time. While 1st fermentation takes 1-4 weeks, kombucha is only sitting in the bottles during 2nd fermentation for 2-6 days.
This means that during 2F there's a lot less time for BPAs and other chemicals to corrode off the plastic or bacteria to develop in the crevices of scratches.
Another big reason why plastic bottles may be ok for 2nd fermentation is that unlike the vessel used for 1st fermentation which is refilled and reused every brew, 2F bottles can be temporary and only used once.
One use bottles means no risk of ruining future brews if scratches or bad bacteria develop, since you’re using an entirely new plastic bottle each time.
And the last reason why you could use plastic bottles for 2nd fermentation is because the 2F bottles do not have the SCOBY in them, only kombucha. This means that if a bottle does get contaminated or ruined, you don’t run the risk of permanently damaging your SCOBY that you’ve worked so hard to grow and take care of.
Now, I do have to say that although plastic bottles are more likely to work for 2F than 1F, glass brewing bottles are still your best option.
Glass brewing bottles that are specifically made for fermenting will not only completely negate any risk of BPA and chemical contamination or bacterial infection in your kombucha, but will also provide the easiest and best carbonation because they are made to be airtight.
Plastic bottles, which aren't made seal airtight and hold in built up pressure will leak out some of the pressure built up during fermentation, leading to a lack of carbonation and a flat or only slightly carbonated booch. Which can be a frustrating problem to fix.
If you’d like to invest in some brewing bottles for your 2nd fermentation of kombucha you can find the set that I own on Amazon here. They’re a set of 6, 16oz high pressure bottles with ceramic lids and stainless steel closures.
Even if you have made the investment in glass brewing bottles, some people still like to fill up 1 plastic bottle every 2F to keep track of how much pressure/carbonation has built up. Once the plastic bottle feels firm, they know that the 2nd fermentation is done and they can open up the glass ones.
I personally just check the level of carbonation by opening one of my glass bottles after a few days. But I wanted to make you aware of the option and let you know that brewing kombucha in plastic can be useful in specific situations.
In summary, plastic should not be used during the kombucha brewing process of 1st fermentation as the acidity in kombucha can release toxins and chemicals such as BPAs from the plastic into the kombucha. Plastic bottles can be used for 2nd fermentation, but won’t create as good of carbonation as quality glass brewing bottles.
Hopefully this article could help you out. If you’d like to learn more about kombucha, how to brew it, and other kombucha related tips, be sure to check out the rest of my website! Have a great day!