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Fermented Vegetables & Fruit

Fermented Green Tomatoes: Brined With Dill and Garlic, and Which Green Tomatoes to Use

By Updated 2 min read

Make tangy fermented green tomatoes using the old-fashioned lacto-fermentation method. Three recipes: classic dill-garlic, Southern-spiced, and stuffed Eastern European style. Ready in 5-7 days.

At a glance

To ferment green tomatoes, use firm, full-size mature-green tomatoes, cut a cross in the blossom end or halve them, and pack them with dill, garlic and spices under a 3% brine (30 g salt per litre of water). Weigh them down and leave at 18–24°C for 1–2 weeks, tasting from day 7; refrigerate once clearly sour. Mature-green tomatoes contain far less of the bitter glycoalkaloid tomatine than tiny immature ones.

  • Use full-size, mature-green tomatoes; tomatine is highest in tiny immature fruit.
  • α-tomatine fell from 361 to 13.8 mg/100 g as green tomatoes matured.
  • Brine: 3% salt by weight (30 g per litre of water).
  • Usually 1–2 weeks at 18–24°C; refrigerate once clearly sour.
  • Tomatoes contain tomatine, not solanine.

Ferment profile

Origin
Home fermentation (traditional in Eastern Europe)
Fermentation
Lactic acid
Main microbes
Wild lactic acid bacteria from the vegetables
Live cultures
Yes
Alcohol
None / trace

Fermented green tomatoes are unripe tomatoes – whole, halved or in wedges – fermented in salt brine with dill, garlic and spices until sour, firm and tangy, much like dill pickles. They’re a classic end-of-season ferment for the tomatoes that won’t ripen before the frost, and they’re traditional in Eastern European kitchens, sometimes stuffed with grated carrot, garlic and herbs. For ripe tomatoes, see our fermented tomatoes.

Which Green Tomatoes to Use

Unripe tomatoes contain glycoalkaloids – mainly α-tomatine and dehydrotomatine – which the plant uses against pests and which give raw green tomatoes their bitter edge (Friedman, 2002). The amount falls steeply as the fruit matures: in one study, α-tomatine dropped from 361 mg per 100 g in the smallest, youngest green tomatoes to 13.8 mg by the time they began to colour, and dehydrotomatine from 48.2 mg to undetectable (Choi et al., 2010). So choose full-size, mature-green tomatoes – firm, glossy and pale green, the kind left on the vine at the end of the season – rather than tiny, hard immature ones. (Tomatoes don’t contain solanine, the potato alkaloid; the tomato’s own are tomatine and its relatives.)

Brine and Timing

Use a 3% brine by weight: 30 g of non-iodized salt per litre of unchlorinated or boiled-and-cooled water. Cut a cross in the blossom end of whole tomatoes, or halve them, so the brine gets inside, and weigh them down firmly – green tomatoes float. At 18–24°C they usually take 1–2 weeks to sour fully; start tasting at about day 7. Refrigerate only when they’re clearly sour: unripe tomatoes, garlic and dill aren’t reliably acidic on their own, and it’s the lactic acid that brings the jar below pH 4.6, the line food-safety rules use for acid foods (21 CFR 114). They aren’t shelf-stable and shouldn’t be canned. A flat white film is usually kahm yeast; fuzzy or coloured mould, a rotten smell or slime mean the batch goes in the bin (NCHFP).

Variations

  • Stuffed (Eastern European style): cut a deep cross in each tomato and press in a mix of grated carrot, minced garlic, dill and parsley before packing and brining.
  • Spiced: celery and mustard seeds, bay and a pinch of cayenne instead of dill.

Fermented green tomatoes contain live lactic acid bacteria when eaten raw, which makes them a fermented food rather than a probiotic (Marco et al., 2021). For the same method with cucumbers, see fermented dill pickles, and if a batch turns soft or misbehaves, our troubleshooting guide can help.

Recipe: Fermented Green Tomatoes with Dill and Garlic

Makes
2 litre (half-gallon) jar
Hands-on
25 min
Fermentation
1–2 weeks at room temperature
Salt
3% brine: 30 g salt per litre of water
Temperature
18–24°C (65–75°F)
Difficulty
Easy

Equipment

  • 2-litre wide-mouth jar
  • Scale
  • Firm fermentation weight
  • Loose lid or airlock

Ingredients

  • 1 kg mature-green tomatoes (full-size, firm, unblemished)
  • 6–8 sprigs fresh dill (or 1½ tsp dill seed)
  • 4–6 cloves garlic, crushed
  • 1 tsp each black peppercorns and mustard seeds
  • ¼ tsp chilli flakes (optional)
  • About 1 litre water (unchlorinated, or boiled and cooled)
  • 30 g per litre of water non-iodized salt

Method

  1. Dissolve the salt in the water (30 g per litre).
  2. Wash the tomatoes and remove the stems. Cut a cross in the blossom end of small ones; halve or quarter large ones.
  3. Put the dill, garlic and spices in the jar and pack in the tomatoes tightly.
  4. Pour over the brine to cover by 2 cm and add a firm weight; green tomatoes float.
  5. Cover loosely or fit an airlock and leave at 18–24°C. Check daily and keep everything submerged.
  6. Taste from day 7. When clearly sour (usually 1–2 weeks), close and refrigerate; eat within a few months.
  7. Discard the batch if you see fuzzy or coloured mould, smell rot, or the tomatoes turn slimy.

Frequently asked questions

Are green tomatoes safe to ferment?

Yes, using full-size mature-green tomatoes. Tiny immature fruit is much higher in the bitter glycoalkaloid tomatine.

Do green tomatoes contain solanine?

No – solanine is the potato's alkaloid. Tomatoes contain α-tomatine and dehydrotomatine, which fall as the fruit matures.

How long do fermented green tomatoes take?

Usually 1–2 weeks at 18–24°C. Taste from day 7 and refrigerate when they're as sour as you like.

What salt percentage should I use?

A 3% brine: 30 g of non-iodized salt per litre of water.

How long do they keep?

A few months in the fridge, kept under their brine.

Can I use tomatillos?

Tomatillos are a different plant; they can be fermented, but this method is for unripe tomatoes.

Sources

  1. Friedman M (2002). Tomato glycoalkaloids: role in the plant and in the diet. J Agric Food Chem 50(21):5751–5780. Link
  2. Choi SH et al. (2010). Changes in free amino acid, phenolic, chlorophyll, carotenoid, and glycoalkaloid contents in tomatoes during 11 stages of growth and inhibition of cervical and lung human cancer cells by green tomato extracts. J Agric Food Chem 58(13):7547–7556. Link
  3. eCFR. 21 CFR Part 114 – Acidified foods. Link
  4. National Center for Home Food Preservation. Causes and possible solutions for problems with fermented pickles. Link
  5. Marco ML et al. (2021). The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nat Rev Gastroenterol Hepatol 18(3):196–208. Link
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