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Storing fresh herbs and basil.

Most herbs keep a few days in the fridge, or up to a week in a jar of water. Basil is the exception: cold turns its leaves black, so it stays out of the fridge.

Wash the herbs, shake them dry, and keep them in the fridge in a loose bag, or stand the stems in a jar of water. Basil is the one to treat differently. It does not like the fridge, and it keeps better on the counter in a jar of water.

A bunch of herbs from the market wilts fast, so a little care on the day you bring it home pays off.

Washing and drying first

The University of Maine extension service says to wash herbs under running water, then shake them dry or use a salad spinner, and blot them with a clean towel. Rutgers makes the same point for basil: dry the leaves after washing and before storing, because wet leaves decay. Rutgers also says to wash only when it's needed, for example when there is soil on the leaves.

In the fridge: bag or jar

Maine describes two ways to keep a bunch of herbs cold.

The first is a bag. Put the washed herbs in an open, perforated plastic bag and set it in the crisper drawer. You can wrap the herbs loosely in a damp paper towel first. Maine says herbs kept this way last roughly 2 to 3 days.

The second is a jar, which lasts longer. Stand the cut stems in a jar or glass with about 1 inch (2.5 cm) of water, cover the top with a plastic bag, and put it in the fridge. Change the water every day. Maine gives 5 to 7 days for this method.

The page talks about herbs in general and doesn't list which ones were tested, so treat the times as a rough guide.

Why basil is different

Most herbs are fine near fridge temperature. Basil is not. The 2023 review in Frontiers in Plant Science says most other herbs keep best at about 0 degrees Celsius, but basil is damaged by cold. Injury starts below 12 degrees Celsius and becomes severe below 10. The same review reports that leaves can blacken in as little as 1 day at 0 degrees, or 3 days at 5 degrees. Fridge cold is well inside that range, so leaves that go in green can come out dark.

Rutgers lists the signs: blackened leaves, discoloured stems and loss of aroma. It gives an ideal storage temperature of 55 degrees Fahrenheit, which is about 13 degrees Celsius, and a relative humidity of 90 to 95 percent. Rutgers also cites University of California work in which basil held between 50 and 68 degrees Fahrenheit (10 to 20 degrees Celsius) looked much better after 10 days than basil held at 32 degrees Fahrenheit (0 degrees Celsius).

For the kitchen, Maine's advice is short: keep basil at room temperature in a jar of water. Rutgers adds that standing the stems in water, or covering the leaves loosely with something that isn't sealed, raises the humidity around them.

How long on the counter

The review gives an average shelf life for basil of 6.8 to 7.3 days at 20 to 25 degrees Celsius, with a wide range of 2 to 14 days. At 15 degrees it was 12.5 days. A warmer room falls outside those figures, so a jar of basil on a Thai kitchen counter is worth a look every day.

The studies are about sweet basil (Ocimum basilicum). The sources don't say whether holy basil (kaphrao) or other basils behave the same way, so that part is left open.

In short

  • Wash herbs under running water, shake them dry and blot them with a clean towel before storing.
  • In the fridge, herbs keep about 2 to 3 days in an open perforated bag, or 5 to 7 days with the stems in about 2.5 cm of water under a plastic bag, changing the water daily (University of Maine).
  • Basil is damaged by cold. Injury begins below 12 degrees Celsius, so it goes in a jar of water at room temperature, not in the fridge.
  • The research cited here covers sweet basil, and the shelf life figures are for 15 to 25 degrees Celsius.

Sources

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