Easy Fermented Zucchini Pickles with Thyme and Lemon

Fermented Zucchini

Zucchini is a type of summer squash that grows very well in Louisiana, and this makes sense since zucchini was first cultivated in Mesoamerica. It grows so well here that it’s all you can get at the Baton Rouge farmer’s market in the summer, making fermented zucchini a great fermentation project.

Zucchini grow on vines, making their indigenous microbiome very similar to cucumbers. Thus, zucchini fermentation is very similar to cucumber fermentation. All zucchini are squash, but not all squash are zucchini. So this recipe applies to fermenting squash too.

Fermenting Zucchini

It’s essential to start with fresh, firm, hydrated zucchini for this fermentation project. You can use these easy tips to ensure your zucchini is optimal for fermentation.

Here’s my checklist for choosing quality zucchini: 

1. Density: The zucchini should feel dense, like it is hydrated and has turgor pressure. It will feel slightly more hollow than a fresh cucumber if you tap your finger against it. 
2. “Check for surface mold: Look for indentions and soft spots in the zucchini. You do not want to buy a zucchini that is squishy and flimsy. Zucchini close to molding will have dark, small, circular indentions or black” pocks” on the surface.”Check for surface mold: Look for indentions and soft spots in the zucchini. You do not want to buy a zucchini that is squishy and flimsy. Zucchini close to molding will have dark, small, circular indentions or black “pocks” on the surface.
3. Small is Better: The bigger the diameter of the zucchini, the soggier your fermented zucchini will be. Go for the smaller dainty zucchini. 
4. Color: Zucchini should be a solid rich green color.
5. Organic: Zucchini is one of those vegetables you want to buy organic. Sometimes conventionally grown “dirty” crops, like summer squash, don’t have a good enough microbiome to initiate the wild fermentation process. Conventionally grown zucchini can contain high amounts of toxic organophosphate and organochlorine pesticides, which kill many microbes. The fermentation will fail if you try to ferment zucchini which does not contain the right microorganisms.

Fermenting Sliced Zucchini

How you slice zucchini impacts how the pickles hold up during fermentation. You should always remove the ends of zucchini and not include the ends in the fermentation. The blossom end of zucchini contains enzymes that can soften the pickles.

For pickle chips, a ripple-cut pickle holds up better than a straight-sliced pickle. You can get a cheap and simple ripple cutter by clicking here.

I also suggest fermenting pickle spears or halves, which hold up even better than pickle chip slices. Spears and halves can be cut with a regular knife.

If you want to ferment a large zucchini that may be overripe and has a spongy texture already, you should ferment it as a relish. Grate it into shreds and ferment it as a relish, so if it’s a little soggy, it won’t matter.

Preventing Sogginess When Fermenting Sliced Zucchini

To help prevent sogginess, start with cold zucchini and a 3.5% total salt concentration. The most important thing you can do to keep your fermented zucchini pickles crisp is to use at least 3.5% total salt.

You can add bay leaves, sencha green tea, and grape leaves for tannins. You can also try adding calcium chloride salt to pickles, which is very effective at keeping things crunchy. (Some sources of calcium chloride are natural from limestone… and some are chemically produced. I suggest researching this salt and deciding if you’d like it in your food).

Don’t forget, as mentioned above, how you slice your zucchini matters. Stick to ripple cuts or spears/halves for the best results.

Zucchini Health Benefits

Why is zucchini such a healthy vegetable? This vegetable is high in water and fiber, making it great for gut health. Green vegetables like zucchini and cucumber contain health-promoting phytochemicals, such as vitamins, fiber, minerals, glucosinolates, and phenolic compounds.

Many of these compounds found in zucchini can help to reduce inflammation and the symptoms of inflammatory conditions. 

Let’s dive deeper into those phenolic compounds, though. Depending on the structure, polyphenols can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives, and flavonoids.

Phenolic compounds are known to be protective against cancer and heart diseases because of their potent antioxidative properties.

These polyphenols become more bioavailable and potent through the microbial action of fermentation. During fermentation, we allow desirable microbes to transform plant fiber and generate more bioactive peptides and polyphenols. 

Fermented Zucchini Pickles

Have you ever heard of GABA? It stands for Gamma-aminobutyric acid. It is a naturally occurring, non-protein amino acid that works as a neurotransmitter in your brain. GABA is studied and produced for its multitude of benefits:

• relieving anxiety
• improving mood
• inhibition of cancer cell proliferation
• reducing symptoms of premenstrual syndrome (PMS)
• aiding in attention deficit-hyperactivity disorder (ADHD) treatment
• lean muscle growth
• stabilizing blood pressure
• relieving muscle pain

Well, it turns out that microorganisms produce GABA in multitudes during the lactic acid fermentation of vegetables!

This is especially true in fermented zucchini and cucumber pickles. Biologically synthesized GABA is more usable by the human body than chemically synthesized GABA. So if you need a mental wellness boost, you can eat some fermented zucchini!

Probiotics in Fermented Zucchini Pickles

Zucchini naturally have a lot of Lactobacillus plantarum on their surface, meaning that it ferments a little faster than other vegetables.

While cabbage takes four weeks to ferment, zucchini takes about two weeks. This abundance of Lactobacillus makes fermented zucchini excellent for gut health. After fermentation, fermented zucchini is loaded with over fifteen beneficial, gut-health-promoting species of Lactobacillus bacteria. 

Here’swhat happens when you ferment zucchini: 

24 – 72 hours: All contents in the jar should be submerged beneath the brine. At this time, Gram-negative bacteria and possible pathogens are still present. 
  
 72 hours – 7 days: After 72 hours, you should start to see lots of bubbles being produced. This is the stage in which you will burp the jar if you are using a standard sealing lid. This is when the ferment enters stage two of vegetable fermentation. Leuconostoc bacteria begin to thrive and produce a lot of carbon dioxide and acetic acid. Gram negative organisms die off during this time. 

7 – 12 days: The bubbles in the brine will decrease as the ferment leaves stage two and enters stage three. The mixture will become cloudy and start to develop a pleasantly sour smell. Lactobacillus species are most abundant during this period.

12 – 14 days: Lactobacillus comprise most or all of the microbial population. They produce copious amounts of lactic acid, making the ferment smell even more pleasantly sour. This is the time in which the vegetable mixture becomes preserved. This is when you want to smell and taste test.

Supplies to Ferment Squash

Here is the equipment you will need to make it:

• 32-ounce Wide Mouth Mason Jar
• Fermentation Weight
• Standard Metal Mason Jar Lid (this can rust in the presence of salt)
• OR Rust-Free Plastic Lid
• OR you can use a Weck Jar (without the gasket; only use the clips to secure the lid)
• Sea Salt
• Scale
• Mixing Bowl 

Care Guide for Fermented Squash

By following directions, you should not encounter this problem. Note that most “vine-growing” wild-fermented vegetables can have pellicle growth. This is normal for vegetables that are also fruits as long as it does not look furry, pink, blue, black, green, or magenta.

A safe pickle pellicle is normally opaque, off-white, and crinkly. If you have surface growth like this, it’s a harmless mixed colony of wild yeasts. It’s not “mold”…you can skim it off the top and still eat your pickles. See the two pictures below as a reference for what a normal pickle pellicle looks like.

Fermented Zucchini Tips

During the first few days of fermentation: carbon dioxide and bubbles will be produced. Sometimes jars will become full of liquid, and this liquid can seep out. You can store the jar in a bowl or plate to catch anything that seeps out.

Remove the lid and tamper everything using a gloved hand, tamper, or spoon if necessary. Make sure everything remains submerged below the brine during fermentation. You can take the lid off regularly and rinse it clean if it is dirty.

Fermented zucchini should smell pleasantly sour and more smooth than a vinegar pickle. Never eat fermented vegetables that smell repulsive or like alcohol. 

How Long Should I Ferment Zucchini?  

See the timeline above. After two weeks, remove the fermentation weight and smell and taste test. Your fermented zucchini should smell pleasantly sour and taste similar to fermented pickles. The texture will be slightly soft since fresh zucchini already has a soft, almost spongy texture.