It is fascinating how little is needed for lacto-fermentation. Under the right conditions, the variables of time, salt and liquid can both preserve and transform a simple food into something downright delicious and nutritious. Essentially, 2 simple rules need to be followed: blocking oxygen from the fermentation container and keeping the fermenting food below the brine.


The brine (saltwater solution) combined with the lack of oxygen creates an acidic environment within the fermentation container. While ideal for the beneficial lactobacillus bacteria responsible for the fermentation process, it is inhospitable for pathogens that could ruin the ferment and possibly make us ill. As long as the salt content is correct, the submerged food is safe and sound under the brine. In some cases, the fermenting food is so tightly packed in the container that it naturally stays put and under the brine. However, not all food behaves the same, and there are often stubborn pieces that float to the surface, escaping the safety blanket of the view of jar filled with brine with a little bit of space left at the top

There are a variety of methods and products that can be used as fermentation weights. Please note although you can be creative using items in your home, it is important that they are properly sanitized and food grade. I will share my preferred method and a few commercial options.


This is my preferred method for all my ferments. I learned this easy method from the great book, Fermented Vegetables by Christopher Shockey Kirsten K Shockey.

First, cover the fermented food using a piece of parchment paper (some people prefer using a cabbage leaf or piece of vegetable cut to size). Next place a freezer bag or sturdy food grade bag into the jar. Fill bag with brine (in the rare case that the bag ruptures, the brine in the container will not be diluted.)ziplock-wieightLid the jar. The water will act as a weight to keep the food submerged during the fermentation period.ziplock-weight-fido

For larger ferments, I use multiple brine-filled ziplock bags to act as weights.


use a smaller glass jar as a weight
use a smaller glass jar as a weight

A smaller jar can be inserted into the mouth of a larger jar and fill with pie weights, beans or water. img_1475This method is more suitable for smaller fermentation projects.  Since the inserted jar weight takes up space within the fermentation container, you are not able to fill the container to capacity with the ferment. img_1453-2

COMMERCIAL FERMENTATION WEIGHTSmason-jar-lifestyle-glass-fermentation-weights-wide-mouth-amazonfermentation weight

These are weights made of food-grade material specifically designed to fit into wide-mouth jars and fermentation crocks. They are excellent, effective tools as long as you don’t have too many ferments on the go (they can be pricey).

8 Responses

  1. I want to try this, don?t have any weight, so just curious. Won?t the parchment paper eventually get soaked.

    1. Hi Vireen- I use parchment paper with no issues. I always put it on the surface of my sauerkraut ferments which take about 4 weeks. It also holds up well when placed on the surface of a brine ferment of approximately 2 weeks total fermentation time.

  2. Thanks for the good info. I opt for the smaller glass jar in a jar for my ferments.
    I typically use half-gallon wide mouth mason jars, inserting the 4 oz regular mouth jar at the top. The small jar only really takes up the neck of the half-gallon jar, so it’s not much of a volume sacrifice.
    Another trick I do with this method is top off the ferment with — rather than a cabbage leaf — a thin but sturdy vegetable disc (e.g. turnip or beet) cut to fit close to the diameter of the neck of the bigger jar. The small jar then pushes down on the topper disc, and the topper disc in turn pushes down on the rest of the ferment — keeping everything needed beneath the brine.
    If you get the ferment and brine volume just right, it works out just perfectly where the vegetables will be below the jar neck, and only a thin ring of brine on the outside of the smaller jar in the neck of the bigger jar will have any air exposure, allowing enough space for carbon dioxide to escape, but no room for ferment food pieces or particles to escape to the top.
    (Hopefully, I articulated that well enough; probably some pictures would help.)
    Anyway, it’s my favorite solution as, 1) the 4 oz mason jars are much less expensive that custom weights, and it’s an all glass and vegetable solution.

    1. Hi John- thanks for sharing your tips! Yes, I like using the smaller glass jars as weights, but they are sometimes hard to find or to fit into some jars. Using the ends of vegetables or cabbage leaves is another great idea. There are so many options that don’t involve having to purchase pricy weights!

  3. I have successfully used rocks as fermentation weights. I took smooth oval flat river pebbles of various sizes and washed them in the dishwasher ( effectively sterilizing them). They fit even into normal sized jars and one or more make a perfect weight to keep the veggies submerged. cost free too!

    1. Hi Atmo- thanks for your interest and comment. Absolutely ok on using river rocks! I haven’t used them in ferments yet,(haven’t found any big enough), but I know of lots of people using them with great success! I have boiled smaller ones and put them in my daughter’s goldfish tank and the fish have been healthy for quite a few years! If I come across larger ones, I will definitely use them for ferments,

  4. I know that my comments might not be appreciated however I still do not understand why anyone would suggest the plastic bag method. I love the Shockeys and I have their fabulous book however putting plastic and all that could end up in your ferment and into your brine just baffles my mind. BPA is replaced with some other BP- and as the brine becomes more acidic, leaching will happen. Why are we doing this

    1. HI Kim- thank you for your comment. I have heard this concern from other people regarding the use of plastic bags with ferments and the concern of BPA contamination into the brine. It would be interesting to find a study that could shed some light on this debate. The bags I use (ziplock) do not contain BPA, as indicated on the box. Alternatively, there are other effective weight options for those that are still uncomfortable with this method.

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