A few courgette plants can turn out more fruit than anyone can eat, and the ones hiding under the leaves turn into marrows. This bright yellow relish uses 1.8kg of them at a time, courgettes or young, firm marrows, with onion, cider vinegar, sugar and whole spices. It is the quick-cooked, finely shredded member of the chutney family, loose and bright rather than thick and dark: five minutes in the pan, then fifteen minutes in a pan of boiling water, and the sealed jars keep in the cupboard.
- Makes
- about 5 x 470ml (US pint) jars, or about 10 x 240ml (half-pint) jars
- Cooking time
- about 5 minutes' boiling, then 15 minutes' processing in boiling water (20 minutes above about 300m)
- Keeps
- best used within a year, unopened, in a cool, dark, dry place
- In season
- courgettes crop from July to October in Scotland
Ingredients
- 1.8kg courgettes (green or yellow) and/or young, firm marrows, weighed whole before trimming
- 70g onion, diced (about 120ml)
- 475ml cider vinegar, 5% acidity
- 450g white sugar (about 530ml in a jug)
- 2 tsp celery seed
- 2 tsp turmeric
- 4 tsp mustard seed
Weigh the squash exactly as picked, before cutting anything off, and check the vinegar label says 5% acidity.
Method
- Wash and rinse the jars and keep them hot until you fill them, and prepare new two-piece canning lids following the maker's directions.
- Put a rack in the bottom of a canner or a deep pan, half fill it with clean warm water and heat it to about 82°C (hot but not boiling) ready for the hot jars.
- Rinse the courgettes, cut off the blossom and stem ends, and shred them in a food processor or by hand. Dicing them small works too.
- Peel the onion, trim the root and stem ends, rinse it and dice it.
- Put the vinegar, sugar, celery seed, turmeric and mustard seed in a large stainless steel or unchipped enamel pan (not copper, brass or iron) and bring to the boil.
- Carefully add the courgettes and onion and bring back to the boil.
- Boil gently for 5 minutes, stirring often.
- Pack the hot relish and its liquid into the hot jars, leaving about 1.25cm of space below the rim. The liquid must cover the vegetables.
- Run a clean skewer round the inside of each jar to release air bubbles, and top up to the same level if needed.
- Wipe the rims with a clean, damp paper towel and put on the lids and screw bands.
- Don't skip this bath: it is what makes the jars safe to keep in the cupboard. Stand the jars on the rack in the hot water, then pour in boiling water around them, not directly onto them, until it is at least 2.5cm above the lids.
- Cover the pan and bring it to a vigorous boil on high heat.
- Once it is boiling, time 15 minutes (20 minutes above about 300m), with the lid on. If the water stops boiling, bring it back to a full boil and start the timing again from the beginning.
- Turn off the heat, take the lid off the pan and wait 5 minutes.
- Lift the jars out upright onto a towel, at least 2.5cm apart. Don't tighten the lids.
- Leave them undisturbed for 12–24 hours, then check the seals (see below), label with the date and store. Put any relish that didn't fit in a jar in the fridge.
Why this relish isn't like apple chutney
Sour apples carry plenty of natural acid. Courgettes carry very little. All fresh vegetables except most tomatoes are low-acid foods, and a mixture of low-acid vegetables with vinegar only becomes an acid food when there is enough vinegar in it. The acid has to reach a minimum, even level right through the jar to stop botulism bacteria growing, so the balance of vinegar to vegetables is what keeps this relish safe in the cupboard.
So keep every quantity as written. Don't reduce the vinegar or the sugar, don't add extra courgettes, onion, garlic or other vegetables, and don't use a vinegar whose acidity isn't stated. Don't add oil either: oil isn't acidic and it shuts out air, which is exactly what botulism bacteria need. Many courgette chutney recipes are oily or low in vinegar, and a tested recipe matters more for courgettes than for apples. There's more on this in the guide to mixing fruit and veg in preserves.
Courgettes, marrows and other squash
A marrow is a courgette left on the plant well past the 10–12.5cm picking size. The recipe was developed with courgettes and yellow summer squash, so use a marrow only while it is still young and firm enough to shred whole, skin and all, like a big courgette. A large, seedy marrow with a hard skin or a soft, pithy middle doesn't belong in this relish. Everything must be fresh, with no soft or rotten patches.
| Squash | In this relish? |
|---|---|
| Green courgettes | Yes |
| Yellow courgettes | Yes, alone or mixed with green |
| Young, firm marrows that shred whole | Yes |
| Large, seedy or hard-skinned marrows | No |
| Winter squash or pumpkin | No |
Never use winter squash or pumpkin. They aren't safe in a relish or chutney kept in the cupboard; pumpkin and squash pickles have to be kept in the fridge.
The full courgette growing guide covers picking little and often, and dealing with a glut of courgettes explains why they all arrive at once.
Jars, lids and the boiling-water bath
The processing time applies only to pint jars (about 470ml) and half-pint jars (about 240ml), both at 15 minutes, with two-piece canning lids (a flat lid and a screw band). Larger jars, clip-top jars and old jam jars with twist-off lids have no processing time for this relish. There's more on closures in the guide to jars for preserving.
The jars don't need sterilising beforehand, because they are processed in boiling water for 15 minutes; wash them and keep them hot. The sterilising guide covers preserves that are hot-filled without a bath.
Long-simmered chutneys are usually hot-filled with the lids on straight away so a vacuum seal forms, but this relish cooks for only five minutes and its cupboard life depends on the bath. Relish that is only hot-filled into jars, including ordinary jam jars with twist-off lids, has no tested keeping time: keep those jars in the fridge and eat them within a few days, as you would an unsealed jar. The end-of-season relish uses the same bath for a mixed glut of tomatoes, cabbage and peppers.
Checking the seal
When the jars have cooled, take off the screw bands and test each lid:
| Test | Sealed | Not sealed |
|---|---|---|
| Press the centre of the lid | Stays down | Springs back up |
| Tap it with a teaspoon | Clear, ringing note | Dull sound |
| Look across it at eye level | Curves slightly downwards | Flat or bulging |
A jar that hasn't sealed can go in the fridge; eat it within a few days. Or reprocess it within 24 hours: check the jar rim for tiny nicks, change the jar if needed, fit a new lid and process for the full time again (15 minutes, or 20 above about 300m).
Storing and opening
| Stage | Where | How long |
|---|---|---|
| Sealed | Clean, cool, dark, dry place (10–21°C), so not a damp shed or an unheated garage in winter | Best used within a year |
| Opened | Fridge | Within a few weeks to a month or two |
Store the jars without their screw bands so the lids stay dry and a broken seal shows straight away. Keep them away from damp, which corrodes metal lids, and away from a cooker, hot pipes or sunlight. Before opening, check the lid still curves downwards. Don't taste relish from a jar with a swollen lid, liquid that spurts out, rising bubbles, an unnatural colour or mould. More on spoilage signs is in how long preserves keep.
Common questions
Can I use a marrow instead of courgettes?
Only a young, firm one that you can shred whole, skin and all, like a large courgette. Weigh it whole before trimming, cut off the blossom and stem ends and shred it.
Should I peel a marrow or take out the seeds?
No. The method trims the blossom and stem ends and shreds the whole fruit. If a marrow needs peeling or seeding, it is too old for this relish.
Can I use less sugar or vinegar?
No. The vinegar is what makes low-acid courgettes safe to store, and changing the proportions takes the relish outside the tested recipe.
Can I use malt vinegar?
No. Use cider vinegar with 5% acidity on the label: that is the vinegar the relish was tested with, and the vinegar proportions and type shouldn't be changed. Never use a vinegar whose strength isn't stated.
Can I use butternut squash or pumpkin?
No. This relish is only for courgettes, marrows and yellow summer squash. Winter squash and pumpkin preserves need to be kept in the fridge.
Can I swap the celery seed?
Yes, celery salt can replace the celery seed if you prefer the taste.
Sources
Show the 16 sources
- Recipe proportions based on: Summer Squash Relish (National Center for Home Food Preservation, University of Georgia; Elizabeth L. Andress, 2015): all ingredient quantities, 5% cider vinegar, yield (about 5 pints), pint or half-pint jars kept hot, preparing lids, trimming blossom and stem ends, shredding or dicing, boiling the liquid then boiling gently 5 minutes, ½ inch headspace, air bubbles, liquid covering the food, wiping rims, processing times (15/20 min), cooling 12–24 hours, yellow/zucchini/combination, celery salt swap, refrigerating leftover relish
- New! Summer Squash Relish (National Center for Home Food Preservation blog): not for use with winter squashes
- Using Boiling Water Canners (National Center for Home Food Preservation): rack, half-filling with warm water heated to 180°F (82°C) for hot packs, pouring water around not onto the jars, at least 1 inch of water over jars, covering the canner, timing from the boil, restarting timing if the boil stops, 5-minute wait, lifting jars upright, 1 inch spacing
- Cooling Jars and Testing Jar Seals (National Center for Home Food Preservation): cooling 12–24 hours, removing screw bands, press, tap and eye-level seal tests, checking for nicks and reprocessing within 24 hours with a new lid and the same time, unsealed jars in the fridge and eaten within several days
- Storing Home-Canned Foods (National Center for Home Food Preservation): clean, cool, dark, dry place at 50–70°F (10–21°C), best used within a year, storing without ring bands, damp corrodes lids, avoiding heat and sunlight, spoilage signs, not tasting from unsealed or spoiled jars
- Sterilization of Empty Jars (National Center for Home Food Preservation): pre-sterilising needed only for jars processed for less than 10 minutes
- Ensuring Safe Canned Foods (National Center for Home Food Preservation): all fresh vegetables except most tomatoes are low-acid; mixtures stay above pH 4.6 unless the recipe has enough vinegar
- General Information on Pickling (National Center for Home Food Preservation): relishes and chutneys as chopped vegetables cooked with seasonings and vinegar; 5% vinegar; don't alter proportions or use vinegar of unknown acidity; minimum, uniform acid level to prevent botulinum growth; fresh, firm produce
- Jellied Product Ingredients (National Center for Home Food Preservation): sour apples have enough natural acid
- Chutney (Penn State Extension): chutney as a relish-type condiment; never reduce the vinegar
- Home Canning Equipment for Making Pickles (University of Nebraska–Lincoln Extension): stainless steel or unchipped enamel pans; no copper, brass or iron
- Food Safety and Labelling Guidance for small scale home producers of chutneys, pickles, flavoured oils and jams (Scottish Borders Council): oil is not acidic and gives an air-free environment for botulism; the amount of vinegar and sugar is essential for safety
- Preserving Winter Squash and Pumpkins (NC State Extension, Henderson County Center): pumpkin and squash pickles must be kept in the fridge
- Courgettes: grow your own (RHS): harvest at 10–12.5cm; left on the plant, courgettes grow into marrows
- Storing Home-Canned Jams and Jellies (National Center for Home Food Preservation): opened jars kept in the fridge (about 1 month for jam)
- 25 dirt-cheap ways to garden organically and save (Garden Organic): opened chutney kept in the fridge (3–4 months)