Bottling & carbonation
There is one job plastic does better than glass, and it is not a job you were expecting.
By Scooter M.·Published September 1, 2026
The short answer
You can, and for the most part you should not. Glass is better for serving and for storage: it does not scratch, does not stain and does not hold odors. The exception is real and worth doing every batch — one food-grade PET soda bottle filled alongside the glass ones is the only pressure reading a home brewer gets.
There is no home equivalent of a pressure gauge for a bottle of conditioning kombucha. You cannot see the pressure and you cannot measure it. What you can do is fill a PET soda bottle from the same batch, cap it, and squeeze it once a day.
As carbon dioxide builds, the bottle goes from squeezable to firm to genuinely hard. That transition is a direct reading of what is happening inside every glass bottle in the batch, obtained without opening anything and losing the fizz you have been building.
It costs nothing — an empty soda bottle from the recycling, rinsed — and it is the single most useful thing you can add to a second fermentation. Once the plastic is hard, the whole batch goes in the fridge.
| Glass | Food-grade plastic | |
|---|---|---|
| Scratches | No | Yes, and scratches hold residue |
| Stains from fruit | No | Yes, especially berries and turmeric |
| Holds odors | No | Yes, over repeated use |
| Published pressure ratings | Available on some bottles | Not published for reused soda bottles |
| Pressure feedback | None — you cannot feel it | Excellent — it goes hard |
| Reusable long term | Yes, indefinitely | A few cycles at best |
| Suitable for serving | Yes | Not really |
Scratching is the substantive objection, not chemistry. Every wash and every bottle brush leaves micro-abrasions in plastic, and those are where residue and organisms sit out of reach. In a bottle you refill weekly for a year, that accumulates. The same argument applies more strongly to fermentation vessels, which are in contact for far longer.
A rated amber bottle for the conditioning stage, and two well-dimensioned glass liter bottles for keeping finished kombucha in the fridge.
EZ Cap
The only bottle here with a published pressure rating — 100 PSI — in amber glass, which is the combination a second ferment actually asks for.
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Bormioli Rocco
Italian soda-lime glass with a published height and diameter and a hermetic clamp seal — the bottle that looks like a bottle, with the dimensions to check it fits a fridge door.
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IKEA
A cheap, well-dimensioned liter bottle with a clamp stopper and a published dishwasher limit — good storage, and explicitly the wrong tool for building pressure.
#ad No live price feed yet, so no number is shown rather than a stale one. How this is funded.
Plastic gets a worse reputation in fermenting circles than the evidence supports, and it is worth being accurate about which objections hold.
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Ranked on the published rubric. Every row jumps to that product's full write-up below; the button goes straight to Amazon.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 | Score8.3 EZ Cap Swing Top Bottles, Amber Glass, 16 oz (Case of 12) The only bottle here with a published pressure rating — 100 PSI — in amber glass, which is the combination a second ferment actually asks for. | Second ferment, one serving at a time | 8.3out of 10 | |
| 2 | Score8.0 Bormioli Rocco Swing Top Bottle, 33.75 oz (1 L) Italian soda-lime glass with a published height and diameter and a hermetic clamp seal — the bottle that looks like a bottle, with the dimensions to check it fits a fridge door. | A bottle you would put on a table | 8.0out of 10 | |
| 3 | Score8.1 IKEA KORKEN Bottle with Stopper, 1 L (34 oz) A cheap, well-dimensioned liter bottle with a clamp stopper and a published dishwasher limit — good storage, and explicitly the wrong tool for building pressure. | Storing finished kombucha, not carbonating it | 8.1out of 10 | |
| 4 | Score7.8 EZ Cap Swing Top Bottles, Amber Glass, 32 oz (Case of 12) The same swing top and amber glass at quart size, which turns a gallon batch into six bottles instead of ten and roughly halves the bottling job. | Bottling a gallon in six moves | 7.8out of 10 |
#1 · Second ferment, one serving at a time
The only bottle here with a published pressure rating — 100 PSI — in amber glass, which is the combination a second ferment actually asks for.
Who it is for. Anyone doing a second ferment who wants a bottle with a number behind it rather than a shape that looks strong.
Source: MoreBeer published EZ Cap product specification (capacity, pressure rating, case contents, crown cap compatibility), morebeer.com/products/ez-cap-swing-top-bottles-amber-glass-16-oz-case-12, fetched 2026-09-01
Skip it if. You want to see the color of the finished drink. Amber hides it; the clear version of the same bottle does not.
#ad No live price feed yet, so no number is shown rather than a stale one. How this is funded.
#2 · A bottle you would put on a table
Italian soda-lime glass with a published height and diameter and a hermetic clamp seal — the bottle that looks like a bottle, with the dimensions to check it fits a fridge door.
Who it is for. Someone bottling a lightly carbonated kombucha for the table, or storing finished kombucha in the fridge rather than conditioning it on a counter.
Source: Bormioli Rocco published Swing bottle specification (capacity, 12.13 in height, 3.5 in diameter, soda-lime glass, hermetic seal, care instructions), retailer specification listings retrieved 2026-09-01
Skip it if. You are chasing hard carbonation. Without a stated pressure rating, a bottle you are deliberately building pressure inside is a bottle you are guessing about — use the rated EZ Cap instead.
#ad No live price feed yet, so no number is shown rather than a stale one. How this is funded.
#3 · Storing finished kombucha, not carbonating it
A cheap, well-dimensioned liter bottle with a clamp stopper and a published dishwasher limit — good storage, and explicitly the wrong tool for building pressure.
Who it is for. Someone who wants somewhere tidy to keep finished kombucha in the fridge, cheaply.
Source: IKEA published KORKEN product specification (capacity, 29 cm height, 9 cm diameter, materials, 70 C dishwasher limit), ikea.com KORKEN product page, retrieved 2026-09-01
Skip it if. You are doing a second ferment on the counter. Nothing published about this bottle supports holding carbonation pressure; use a rated swing top instead.
#ad No live price feed yet, so no number is shown rather than a stale one. How this is funded.
#4 · Bottling a gallon in six moves
The same swing top and amber glass at quart size, which turns a gallon batch into six bottles instead of ten and roughly halves the bottling job.
Who it is for. An established brewer bottling a gallon a week who is tired of filling ten bottles.
Source: MoreBeer published EZ Cap 32 oz amber listing, same product line as the specified 16 oz, morebeer.com/products/ez-cap-swing-top-bottles-amber-glass-32-oz-case-12, retrieved 2026-09-01
Skip it if. You are new to second ferment. Learn what your kitchen does to carbonation in 16 oz bottles, where the consequences are smaller.
#ad No live price feed yet, so no number is shown rather than a stale one. How this is funded.
Every specification cited on this page came from one of these documents, retrieved on the date shown against the product it belongs to.
Bottles compared on published pressure ratings, closure type, glass color and size — and which bottles must never hold a second ferment.
Which bottles are built for pressure, which only look like it, and how to run a second ferment without cleaning kombucha off a ceiling.
Glass, ceramic, stainless and plastic ranked for a pH-3 liquid — with the lead question on ceramic and the scratch problem on plastic.
What the second ferment is, how much sugar to add, how long it takes, and how to know when to refrigerate without opening every bottle.
The five causes of a flat second ferment, ranked by how often each is actually the problem — starting with the one nobody checks.