Freezing preserves the flavour of soft herbs such as basil, parsley and coriander far better than drying. How to freeze them whole, chopped, in oil or water, and how long they keep.
Why freeze¶
Soft herbs lose most of their fresh aroma when dried, because their key flavour compounds are highly volatile. Freezing locks those compounds in. The trade-off is texture: ice crystals rupture the cell walls, so thawed herbs are limp and dark. They are perfect stirred into soups, stews, sauces, curries and dressings, but no good for a salad or a pretty garnish.
Herbs that freeze well: basil, parsley, coriander, dill, chives, chervil, tarragon, mint, lovage, sorrel, wild-garlic, lemongrass, makrut lime leaves and curry leaves. Woody herbs freeze well too, though they also dry perfectly well.
Method 1: whole leaves or sprigs (open-freezing)¶
- Wash and dry thoroughly.
- Spread in a single layer on a tray lined with baking paper.
- Freeze for 1–2 hours until firm.
- Tip into a freezer bag, press out the air, seal and label.
Because each leaf froze separately, you can take out a handful at a time. Frozen parsley and dill crumble easily straight from the freezer: squeeze the bag to "chop" them.
Makrut lime leaves, curry leaves and lemongrass stalks need no preparation: bag and freeze them whole. They keep their flavour very well and are used straight from frozen.
Method 2: chopped, in oil¶
Oil coats the herbs and protects them from freezer burn and browning. Ideal for herbs destined for cooking.
- Chop the herbs roughly.
- Pack into ice-cube trays, about two-thirds full.
- Top up with olive or neutral oil to cover.
- Freeze until solid, then pop out into a labelled bag.
A cube drops straight into a pan of softening onions or a pot of soup. This is also a good way to store pesto (freeze without the cheese, and stir it in after thawing, as many cooks prefer), chimichurri and green-chutney.
Method 3: chopped, in water or stock¶
As above, but covered with water or stock. Useful for soups and stews, less good for frying. Mint or borage flowers frozen in water make decorative ice for drinks.
Method 4: blanched basil¶
Basil blackens quickly in the freezer. To keep it greener, plunge the leaves into boiling water for about 5–10 seconds, then straight into iced water, dry thoroughly, and freeze by either method above. The brief blanch deactivates the enzymes responsible for browning. Some flavour is lost; many cooks think the colour is worth it, particularly for pesto.
⚠️ Garlic and oil
Garlic or fresh herbs in oil at room temperature or in the fridge can support the growth of Clostridium botulinum, the bacterium that causes botulism. Freezing stops it growing, so herb-and-garlic oil cubes are safe kept frozen. Use them straight from the freezer, do not thaw and keep them, and do not leave them at room temperature. See infusing-oils.
How long they keep¶
Frozen herbs remain safe indefinitely at −18°C, but flavour fades. Use within about 6 months for the best results, and label everything: frozen parsley and frozen coriander look identical.
Using frozen herbs¶
- Add straight from frozen; there is no need to thaw.
- Use roughly the same quantity as fresh.
- Add at the same stage you would add fresh herbs, usually near the end of cooking (see when-to-add-herbs-and-spices).
🛟 Dark, freezer-burnt herbs
Freezer burn comes from air contact. Press all the air out of bags, or use the oil method, and use herbs within a few months. Browned herbs are safe to eat but taste flat; use them in stocks rather than sauces.