The Science of Salt & Safety
Why guessing "a pinch of salt" ruins your pickles.
Why Salinity Matters (It's Not Just Taste)
In lacto-fermentation, salt isn't just a seasoning—it's a bodyguard. It creates an anaerobic environment where:
- Bad Bacteria Die: Pathogens like Botulism and E. coli cannot survive in saline environments above 2%.
- Good Bacteria Thrive: Lactobacillus (the probiotics) love salt and will start converting sugars into lactic acid.
- Crunch is Preserved: Salt hardens the pectins in vegetables, preventing your pickles from turning into mush.
What Salt Should I Use? (The Density Trap)
This is the #1 mistake new fermenters make. They read a recipe that says "1 tablespoon of salt," but they use the wrong brand. Salt density varies wildly:
💎
Diamond Crystal
Light & Flaky
9g / Tbsp
☂️
Morton Kosher
Dense Flakes
14g / Tbsp
🧂
Table Salt
Tiny Crystals
18g / Tbsp
As you can see, Table Salt is twice as salty by volume as Diamond Crystal. Always use weight (grams) or our calculator to convert!
When to Use Which Percentage?
Not all veggies need the same brine. Here is the general rule of thumb for fermenters:
| Salinity % | Best For | Outcome |
|---|---|---|
| 2.0% - 2.5% | Sauerkraut, Kimchi, shredded veggies | Fast ferment, mild sourness. |
| 3.5% - 4.0% | Whole cucumbers, carrots, garlic | Standard crunch, mold protection. |
| 5.0%+ | Hot peppers (Mash), long-term storage | Very slow ferment, prevents yeast. |
Frequently Asked Questions
Should I use hot or cold water? ▼
It helps to dissolve the salt in a small amount of warm water first, then dilute it with cold water. Never pour boiling water directly over your vegetables—it will kill the natural bacteria needed for fermentation!
What is the white film on top? ▼
That is likely Kahm Yeast. It's harmless but tastes funky. It happens when salinity is too low or air gets in. Skim it off, and next time, try increasing your salt ratio by 0.5%.
Can I use Iodized salt? ▼
Avoid it if possible. Iodine is an anti-microbial agent that can inhibit the good lactobacillus bacteria. It can also turn your brine cloudy and give pickles a metallic taste. Stick to sea salt or kosher salt.