This mason jar fermenting recipe is the work of Marina Jade Phillips, Fermenter extraordinaire, using our Pickle Helix and Fermenting Lids.

Traditional chimichurri uses oregano, cilantro, and parsley, but this recipe will work with just about any strongly flavored fresh green and/or herb—mustard greens, kale, lambs quarter (an edible “weed”), parsley, oregano, cilantro or marjoram—to name a few. Each alone or in combination will impart different characteristics on the finished product—feel free to experiment!

A Note on “Clean”

A note on “clean” – In fermentation adventures, all equipment should be very clean. If you are unsure about the potentially sordid past of fermentation container, submerge it in water, bring to a boil for a few minutes, and follow with an air dry. A simple soap and hot water wash followed by air drying should be sufficient for a new jar.


  • Watercress. Enough to fill a quart mason jar 3/4 of the way when finely chopped.
  • 1-quart non-chlorinated water.  
  • 1 tbsp. refined sea salt.
  • Chilies. Whole or flaked, dried or fresh.  It’s always possible to add more later in the fermentation process, so those concerned about spice can bein with about a tsp. and work up from there.
  • Garlic.


Save the fancy salts for cooking. Fermentation fairs best with boring salt—the minerals in pink or Celtic salts can leave veggies mushy or metallic. Make sure there are no anti-caking agents (if it pours when its raining, don’t use it!) or iodine. Look for refined sea salt or canning salt.


The Process

1 | Bring the water and salt to a boil.  Set aside and allow to cool at room temperature.

2 | Finely chop all leaves with a knife. A food processor tends to bruise the leaves and the final product could have a less than pleasant pasty texture—but again, feel free to experiment!

3 | Mix chilies, garlic and chopped leaves in a big bowl, then use a funnel to aid the transfer into a quart jar. Use a fork to mash the mixture down as the jar is filling.

4 | Place a Pickle Helix spring on top of the greens, and then pour over the cooled, salted water until the greens are fully submerged, leaving about 1 1/2″ of air space at the top. Compress the spring and tightly screw down a Trellis + Co airlock lid to hold the spring in place. Store at room temperature placed away from direct sunlight.

5 | After three to five days, bubbles should begin to form—this is a sign that beneficial microbes are beginning to work their fermentation magic. After five days, open the jar and give everything a good sniff. There should be a sour odor, the next sign that resident microbes are working to lower the jars’ PH.

6 | Feel free to remove the spring and use a clean spoon to have a taste test. The spice of the watercress will have mostly vanished. The spice of the chilies can become stronger at first and then mellow with time. After ten days it should have a fairly sour flavor and can be refrigerated. More chilies can be added at any time in the process.

Smart Ideas

1 | Save the Brine:

Any leftover brine (the boiled and salted water called for in each recipe) can be stored in a clean jar on a pantry shelf indefinitely. Feel free to make a gallon at a time (keeping the ratio of one tablespoon of salt per quart) as it can be handy to have some around when the fermentation inspiration strikes!

2 | Consider the Surface:

There is always a possibility that the energetic action of bubbling fermentation will force some liquid out of the jar during the initial room temperature ferment. Putting the jar in a shallow bowl is a fine practice.  We advise that you avoid leaving the jar on grandma’s heirloom hutch, just in case. Always leave some air at the top of the jar so there is room for microbial shenanigans.

This is a ferment whose flavor tends to change sometimes quite dramatically over time. Fresh watercress can be incredibly spicy but very little of that quality remains after the fermentation process. Making several smaller batches with different combinations of leaves and herbs creates possibilities for a variety of saucing surprises as flavors merge and then mellow.

Try it the Argentinian way—as the marinade and/or topping to grilled beef steaks. Use as the base of a light salad dressing, adding a bit of oil and a generous amount of fermented liquid from the jar (or steal the liquid of another jar of fermented goodies) and perhaps some soy sauce or tamari. Mix with cream cheese and sour cream for a fantastic picnic chip/veggie dip. Rub into the interior of a trout before baking and top with more after pulling off the skin. Mix with mayonnaise for added interest on sandwiches or hamburgers.

Easy Print Recipe

Click here to access the short, sweet, and printable version of this mason jar fermenting recipe.

Marina Jade Phillips

Marina Jade Phillips

Fermenting Specialist, Interesting Human Being

Born in Alaska and raised in Colorado, Marina discovered the joys of fermentation in Philadelphia in 2005. She spent the last decade wrangling a homestead in Northern California, fermenting everything from tomatoes to beans. Currently, she is pedaling and eating her way thru Mexico on her first but probably not last bicycle tour, toting a violin and at least one jar of sauerkraut.

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