Fermentation Food Preservation

Food preservation techniques including fermentation, pickling, canning, drying, and smoking. Use when someone wants to preserve harvests, extend food shelf life, reduce waste, make fermented foods (kimchi, sauerkraut, yogurt, bread), or build food resilience.

# Fermentation & Food Preservation

Humans preserved food for 10,000 years before refrigeration existed. Fermentation, drying, salting, smoking, and canning are not quaint hobbies — they're core survival technology. A $5 head of cabbage and a tablespoon of salt becomes sauerkraut that lasts 6 months. A bushel of cucumbers becomes 30 jars of pickles. A sourdough starter lives forever and costs nothing after day one. This skill covers the practical methods, starting with the easiest (lacto-fermentation, which needs only salt and a jar) and progressing to canning and dehydration. Safety rules for each method are included because botulism is real and preventable.

```agent-adaptation
# Localization note
- Canning standards:
  US: USDA Complete Guide to Home Canning (nchfp.uga.edu)
  UK: MAFF guidelines
  AU: CSIRO food preservation guidelines
  CA: Health Canada home canning safety
- Altitude affects canning: boiling point decreases with elevation.
  Above 1,000 ft (305m), processing times and pressures must be adjusted.
  Agent must ask user's altitude for any canning guidance.
- Temperature units: Fahrenheit (US) vs Celsius (everywhere else).
  Provide both for all temperature references.
- Measurement: US cups/tablespoons vs metric grams/mL.
  Fermentation ratios by weight (grams) are more reliable than by volume.
- Local food safety authorities vary — swap USDA for equivalent
- Jar types: Mason/Ball jars (US/CA), Kilner jars (UK), Le Parfait (EU),
  Weck (DE). Two-piece lid systems are standard for water bath canning.
```

## Sources & Verification

- **USDA Complete Guide to Home Canning** -- the definitive US reference for safe canning procedures. https://nchfp.uga.edu/publications/publications_usda.html
- **National Center for Home Food Preservation (NCHFP)** -- research-based preservation guidance from the University of Georgia. https://nchfp.uga.edu
- **Sandor Katz, "The Art of Fermentation"** -- comprehensive reference on fermentation techniques worldwide
- **Ball Blue Book of Preserving** -- practical canning recipes and procedures, updated regularly
- **Anthropic, "Labor market impacts of AI"** -- March 2026 research showing this occupation/skill area has near-zero AI exposure. https://www.anthropic.com/research/labor-market-impacts

## When to Use

- User wants to make sauerkraut, kimchi, pickles, or other fermented foods
- User has a garden harvest and needs to preserve it
- User wants to start a sourdough bread starter
- User wants to learn water bath canning (jams, pickles, tomatoes)
- User wants to dehydrate foods (jerky, fruit leather, herbs)
- User wants to reduce food waste by extending shelf life
- User wants to understand food preservation safety (especially botulism prevention)
- User is building food resilience and self-sufficiency

## Instructions

### Step 1: Start with lacto-fermentation (the easiest method)

**Agent action**: This is the entry point for everyone. It requires no equipment, no heat, no special skills. Just salt, vegetables, and a jar.

```
LACTO-FERMENTATION — how it works:

THE SCIENCE (simple version):
Lactobacillus bacteria are already on your vegetables. Salt creates
an environment where Lactobacillus thrives and harmful bacteria can't
survive. The bacteria convert sugars into lactic acid, which preserves
the food, creates the sour flavor, and makes it probiotic.

YOU NEED:
- A glass jar (quart/liter Mason jar is ideal)
- Fresh vegetables
- Non-iodized salt (kosher salt, sea salt, or pickling salt —
  iodized table salt can inhibit fermentation)
- Water (if making a brine — unchlorinated; if your tap water is
  chlorinated, let it sit uncovered for 24 hours or use filtered)

THE UNIVERSAL RATIO:
- For dry-salted ferments (sauerkraut, kimchi): 2% salt by weight
  of the vegetables. For 1 kg (2.2 lbs) cabbage, use 20g salt
  (about 1 tablespoon).
- For brine ferments (pickles, vegetables in liquid): 3-5% brine.
  For 1 liter water, use 30-50g salt (2-3 tablespoons).

BASIC SAUERKRAUT (your first ferment):

Ingredients:
- 1 medium head green cabbage (about 2 lbs / 900g)
- 1 tablespoon (18g) non-iodized salt

Method:
1. Remove outer leaves (save one). Quarter cabbage, remove core.
2. Slice thin (1/8 inch / 3mm). A knife works. A mandoline is faster.
3. Put sliced cabbage in a large bowl. Add salt.
4. Massage and squeeze the cabbage with your hands for 5-10 minutes.
   The salt draws water out of the cells. You're making your own brine.
   Keep going until the cabbage is limp and there's liquid pooling
   in the bottom of the bowl.
5. Pack cabbage tightly into a clean quart jar, pushing down hard
   with your fist or a wooden spoon. The brine should rise above
   the cabbage. Leave 1-2 inches of headspace.
6. Place the saved outer leaf on top as a "cap" to keep shreds
   submerged. Weight it down (a small jar filled with water works,
   or a zip-lock bag of brine).
7. Cover loosely (the jar will off-gas CO2 — don't seal airtight
   or pressure builds. A loose lid, cloth, or airlock all work).
8. Leave at room temperature (65-75F / 18-24C), out of direct sunlight.
9. Check daily. Push cabbage down if it rises above the brine.
   Skim any white scum (kahm yeast — harmless but ugly).
10. Taste after 3 days. It's "done" when you like the sourness.
    Most people prefer 1-3 weeks.
11. Once it tastes right, seal and refrigerate. It lasts 6+ months
    in the fridge.

YIELD: 1 medium cabbage = 1 quart (1 liter) sauerkraut

COST: ~$2-3 per quart (vs $5-8 store-bought for inferior product)
```

### Step 2: Fermented pickles and kimchi

**Agent action**: Once the user has made sauerkraut, these are natural next steps using the same principles.

```
FERMENTED DILL PICKLES (brine method):

Ingredients:
- 2 lbs (900g) small pickling cucumbers (Kirby or similar)
- 4 cups (1L) water
- 2 tablespoons (36g) non-iodized salt
- 4 cloves garlic, smashed
- 2 tablespoons dill seed (or a few heads of fresh dill)
- 1 teaspoon black peppercorns
- 1 grape leaf, oak leaf, or bay leaf (tannins keep pickles crunchy)

Method:
1. Dissolve salt in water to make brine.
2. Cut 1/16 inch off the blossom end of each cucumber (contains an
   enzyme that makes pickles soft). Stem end is fine to leave.
3. Pack cucumbers vertically in a half-gallon jar.
4. Add garlic, dill, peppercorns, and leaf.
5. Pour brine over cucumbers. All cucumbers must be submerged.
6. Weight down. Cover loosely.
7. Room temperature, 3-7 days. Taste daily starting at day 3.
   Half-sours: 3-4 days. Full sours: 5-7 days.
8. Refrigerate when they taste right. Last 2-3 months.

YIELD: 2 lbs cucumbers = half-gallon jar of pickles
COST: ~$3-4 per half gallon (vs $6-8 store-bought)

---

BASIC KIMCHI:

Ingredients:
- 1 medium napa cabbage (about 2 lbs / 900g)
- 1/4 cup (72g) non-iodized salt
- 1 tablespoon grated fresh ginger
- 4 cloves garlic, minced
- 2-4 tablespoons gochugaru (Korean red pepper flakes —
  available at Asian grocery stores; regular red pepper flakes
  work but taste different)
- 1 tablespoon fish sauce (or soy sauce for vegan version)
- 1 teaspoon sugar
- 4 scallions, cut into 1-inch pieces
- 1 medium daikon radish or carrots, julienned (optional)

Method:
1. Quarter cabbage, cut into 2-inch pieces.
2. Toss with salt in a large bowl. Let sit 1-2 hours, tossing
   occasionally. Cabbage will wilt and release water.
3. Rinse cabbage 3 times under cold water to remove excess salt.
   Squeeze out water.
4. Mix ginger, garlic, gochugaru, fish sauce, and sugar into a paste.
5. Combine cabbage, paste, scallions, and radish/carrots.
   Mix thoroughly with gloved hands (gochugaru stains and burns).
6. Pack into a jar. Press down until brine covers vegetables.
7. Leave 2 inches headspace (kimchi is active — it bubbles a lot).
8. Room temperature 2-5 days. Burp the jar daily (open lid to
   release CO2).
9. Taste at day 2. Refrigerate when tangy enough for your taste.
10. Gets more sour over weeks in the fridge. Lasts 3-6 months.

YIELD: 1 cabbage = 1 quart kimchi
COST: ~$4