Bottling & carbonation
A second fermentation is a small pressure vessel on your counter. Most bottle listings never mention pressure at all.
By Scooter M.·Published September 1, 2026
The short answer
Use the EZ Cap 16 oz amber swing top. It is the only bottle here with a published pressure rating — 100 PSI — and it accepts a 26 mm crown cap as well, which is what the maker recommends for long storage. Everything else on this page is a good bottle for storing finished kombucha and a guess for conditioning it.
In a second fermentation, yeast eats added sugar in a sealed bottle and produces carbon dioxide that cannot escape. Some dissolves into the liquid — that is the fizz — and the rest raises internal pressure. How much depends on temperature, how much sugar you added, how active the culture was and how long you left it, and no home brewer is measuring any of that.
Since the process is uncontrolled, the margin has to be in the bottle. Which makes it remarkable how few bottles state what they can take. Of the four here, exactly one does.
| Bottle | Capacity | Closure | Pressure rating | Glass |
|---|---|---|---|---|
| EZ Cap amber | 16 oz | Swing top + 26 mm crown | 100 PSI, published | Amber |
| EZ Cap amber | 32 oz | Swing top | Not published for this size | Amber |
| Bormioli Rocco Swing | 33.75 oz | Hermetic swing top | Not published | Clear |
| IKEA KORKEN | 34 oz | Clamp stopper | Not published, not marketed for it | Clear |
EZ Cap publishes 100 PSI for its 16 oz bottle. It does not state a figure for the 32 oz in the same line, and we do not carry the number across, because a larger bottle has a larger surface area at the same pressure and the maker chose not to make the claim.
This is exactly the sort of quiet assumption that turns into a broken bottle, and it is why our methodology forbids transferring a figure between models even within one product family.
The rated bottle for a second ferment, and two well-dimensioned liter bottles for keeping finished kombucha in a fridge — which is a different job with different requirements.
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.
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Amber glass filters visible and near-ultraviolet light, and a bottle conditioning on a counter for three days near a window gets far more light than one in a dark cupboard. Light degrades the drink over time.
Clear glass shows the color, which matters when you have made something with hibiscus or blackberry in it and want to hand it to someone. The practical split: amber for the counter stage, clear for anything going straight into a dark fridge.
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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 | 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 | |
| 4 | 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 |
#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 · 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.
#4 · 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.
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.
Why a perished gasket is the most common cause of a flat second ferment, how to test a seal in two minutes, and when to replace.
How many bottles a gallon fills at each size, and the real trade-off: fewer bottles to fill against faster loss of fizz once opened.
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.