Simple Sauerkraut: Your First Jar, by the 2% Rule

First-ferment guide 🥬 · Cellar crew · Nov 2026

On this page: the 2% math · jar + gear · the steps · the checkpoint days · the wizard does the dates

The whole recipe is one number

Kraut is the friendliest first ferment there is: one vegetable, one kind of salt, one percentage. The app's sauerkraut recipe sets 2% salt, of the vegetable's weight — that base (the vegetable, not the water) is the whole trick. Weigh your sliced cabbage, and the salt is two percent of it.

The worked example: 500 g of sliced cabbage → 500 × 0.02 = 10 g of salt. That's the entire math. The app's recipe starts at a bigger batch — 1,000 g of cabbage, which works out to 20 g of salt — but 500 g works exactly the same way.

Sliced cabbage	Salt at 2%	Note
500 g	10 g	This guide's worked example — a real first-batch size
800 g	16 g	The app's one-quart jar size: UVM packs 800 g of cabbage into a 1-quart wide-mouth jar
1,000 g	20 g	The app recipe's opening values

Use canning or pickling salt — no iodine, no anti-caking agents. Weigh, don't measure by volume: the percentages are honest only when both numbers are real.

What to gather

Gear	Why
A firm head of cabbage	The whole ferment — crisp and fresh over tired and floppy
Canning or pickling salt	Draws the brine and selects for the good microbes
A jar or crock, a clean cabbage leaf, a fermentation weight	The leaf and weight keep everything under the brine — air is the surface's enemy

The steps

Pull off the outer leaves, quarter the cabbage, cut out the core, and slice it thin.
Weigh the sliced cabbage and enter the weight in the Ferment Wizard's dry-salt lane. Weigh out the salt it gives — 2% of that weight.
Mix the salt in and let it stand for about 30 minutes, until it starts to release juice.
Pack it tightly into the jar, pressing down until the brine rises over the top.
If the juice doesn't cover it, top up with NCHFP's brine: 1½ tablespoons of salt per quart of water, boiled and cooled.
Cover it with the cabbage leaf and the weight, and ferment at 70–75 °F (21–24 °C) for 3–4 weeks. Above 75 °F it can turn soft; below 60 °F it may not ferment.
Check it 2–3 times a week and skim off any film. It's ready when tart and still crunchy — then refrigerate it.

The checkpoint days

These are the sauerkraut template's checkpoints — the same five the app saves with a batch (its plan lists NCHFP and UVM as sources, and the wizard prints them as real calendar dates):

Day	The checkpoint
Day 3	Check it's under the brine, and skim any film
Day 7	Check the brine and skim any film
Day 14	Taste it
Day 21	Taste it: ready when tart and still crunchy
Day 28	Done at 70–75 °F: refrigerate it

So the honest version of "when is it done": taste around day 14, judge it by day 21, and call it done by day 28 at the latest — three to four weeks at room temperature, exactly as the recipe's line says.

The wizard does the dates

You could do all of that on paper — but the Ferment Wizard takes your cabbage weight, works out the salt, and turns those five checkpoints into real dates on a printable bench sheet. The recipes shelf carries the sauerkraut recipe alongside its 19 companions, the log sheets want your notes, and the vegetables guide covers the brine method for everything that isn't shredded cabbage. The full cellar — every calculator, every saved batch — lives in the app.

Weigh it, salt it at 2%, keep it under the brine, taste at two weeks. That's sauerkraut. — the cellar crew