Best Fermentation Weights for Mason Jars

For most people fermenting in a wide-mouth mason jar, the Nourished Essentials Easy Weight is the glass weight to buy. If you are filling a whole shelf of jars and want the cheapest proper glass per jar, buy Masontops Pickle Pebbles. If your ferments run a month or longer, the Trellis + Co. Pickle Helix, a stainless steel spring, held brine over the vegetables longest in the one published side-by-side test. If you only run one jar at a time, a 4-ounce glass jelly jar you already own did better than any of them. The picks weigh three things: whether the weight is a food-safe, non-porous material, whether it fits a wide-mouth opening, and how long it kept vegetables under the brine in published measurements.

The Kenley glass weight with the grip handle is not on the list. None of the sources behind this article publish its diameter, weight or price, and no independent test of it turned up, so there is nothing to judge it on yet.

Mold needs air. The University of Illinois Extension puts it plainly: exposure to oxygen encourages both mold and yeast. That is why every extension service tells you to keep vegetables 1 to 2 inches below the brine for the whole ferment. A weight is simply the thing that holds them there while fermentation gas tries to lift them.

The evidence on how much a weight matters is thinner than the product listings suggest. The most detailed test is Holly Howe's at MakeSauerkraut, which measured brine coverage over seven weights for 28 days (last updated October 14, 2024). Every weight did its job through the first week, the riskiest stretch for mold. After that they diverged. And a control jar with no weight at all finished without mold. Her summary: "All the weights tested work."

So a weight is insurance, not magic. It is one person's test, and what would settle the rankings is the same comparison repeated across many batches.

On sizing: a wide-mouth jar opening is about 2.75 inches (70mm), according to FermentHive. Glass weights for wide-mouth jars run 64 to 70mm, and Ferment Foundry recommends a weight at least 80 to 90% of the mouth's width so vegetables cannot slip past it. FermentHive suggests leaving roughly a quarter inch around the edge so gas bubbles can escape.

This is a glass weight with grooved handles, the grooves being what you grip to pull it out of a full jar. In Howe's 28-day test it stayed in contact with the brine until day 16, more than twice as long as the Pickle Pebble. Her more recent guide at MakeSauerkraut, updated August 5, 2026, names Nourished Essentials as its recommended glass weight.

Glass is the material the sources agree on. MakeSauerkraut calls it the safest option because it is food-safe and non-porous, the same material as the jar. Ferment Foundry reports that glass weights are dishwasher-safe and can last hundreds of ferments unless dropped.

Price: none of the sources here give one, so check the current listing.

The drawback: it still lost brine contact before the month was out. For a sauerkraut you plan to leave four weeks, you will need to check it in the third week.

Skip it if you routinely ferment for a month or more; the spring below held longer.

Pickle Pebbles are flat glass discs sold in both standard-mouth and wide-mouth sizes, according to Cultures For Health. The Ferment Guide listed the 4-pack at about $24 when it last updated on July 22, 2026, roughly $6 a weight, and rated it Best Overall. That per-weight price sits at the low end of the $6 to $10 FermentHive reported for single glass weights on July 17, 2026. The sources do not separate the Pickle Pebbles Plus model from the standard one, so confirm which version a listing is selling and that it says wide-mouth.

The drawback: in Howe's measurements the Pickle Pebble had to come out by day 7 with no brine over it at all, the weakest result in the test. It covered the first week, which is when mold risk is highest, but not beyond.

Skip it if you run long ferments, or if you ferment one jar at a time and could use a jelly jar instead. It makes sense for quick pickles and short ferments where you want a matching weight in every jar.

This one is not glass. It is a coil of 316-grade stainless steel, which The Ferment Guide describes as food-grade and corrosion-resistant. You compress it under the jar lid and it presses down on the vegetables, the way a spring in a ballpoint pen pushes the tip out. As the ferment settles or swells, the spring keeps pushing.

That is why it ranked first in Howe's test, with 12mm of brine still over the vegetables on day 28. The Ferment Guide claims the coils exert roughly three times the downward force of the heaviest glass weights; that figure comes from an affiliate buying guide, not a measurement you can check. It listed a 3-pack at about $28 on July 22, 2026, around $9 a coil.

The drawback: it costs more per jar than Pickle Pebbles, and it only works with a lid on top to push against.

Skip it if your ferments are done in a week or two. Every weight in the test handled that.

A 4-ounce Ball jelly jar set inside a wide-mouth jar kept 18mm of brine over the vegetables at day 28 in Howe's test, the best coverage of anything she measured. Cultures For Health suggests the same trick and adds that you can fill the small jar partway with water for more weight. It is glass, so it shares every safety advantage of a purpose-made weight, and it costs nothing if you already can.

The drawback: it has to fit through the mouth with room to spare, and it must be free of chips or cracks, which Cultures For Health flags for any jar used in fermenting.

Skip it if you need a weight for every jar on a shelf and would rather not tie up your jelly jars.

Two other free options work in a pinch. A large cabbage leaf tucked over the vegetables can hold them down on its own, according to Cultures For Health. A zip-top bag of brine conforms to any jar; the National Center for Home Food Preservation says to fill it with brine rather than plain water (its crock-sized recipe is 3 quarts of water with 4½ tablespoons of salt) so a leak does not dilute the ferment. Ferment Foundry's author had exactly that happen on batch 21 and recommends bags only for short ferments of 2 to 4 weeks.

The rule from Cultures For Health is that anything touching the brine must be food-safe and must not react with an acidic brine. The sources name these to avoid:

• Stones and rocks not made for food. FermentHive warns they risk leaching minerals or heavy metals and are hard to sanitize.
• Porous ceramic in a jar. Ceramic absorbs odors and bacteria over time, per The Ferment Guide. The two-piece ceramic weights sold with stoneware crocks are made for those crocks and do not fit mason jars, according to Ferment Foundry.
• Non-food-grade plastic. "Do not use garbage bags or trash liners," the NCHFP says.

The sources here do not test specific metals such as aluminum or copper. The one metal they describe as suited to fermenting is 316-grade stainless steel.

Crocks do better than jars on spoilage: the NCHFP notes that quart and half-gallon mason jars have higher losses than crocks. Its method for a crock needs no special weight. Set a dinner plate or glass pie plate slightly smaller than the opening on the vegetables, then weight it with 2 or 3 sealed quart jars of water, or a food-grade bag of brine. If you want purpose-made glass, The Ferment Guide listed Stone Creek Trading Luna crock weights at about $38 in July 2026. The rest of the jar method, from salt ratios to fermenting temperature, is in our guide to fermenting vegetables at home.

• Nourished Essentials Easy Weight: most wide-mouth jar fermenters.
• Masontops Pickle Pebbles (wide-mouth): a shelf of jars, short ferments, lowest glass cost per jar.
• Trellis + Co. Pickle Helix: ferments left a month or longer.
• A 4-ounce glass jelly jar: one jar at a time, no spending.
• Plate plus water-filled jars: crocks.

If you wanted a heavier glass weight with a handle, such as the Kenley, wait until its maker publishes a diameter and weight you can check against the 2.75-inch opening, or until an independent test measures it alongside these.