Storing half an avocado, lemon and onion without plastic

Half an avocado, half a lemon and half an onion usually end up in cling film, because it is quick. There is a simpler way, and it works better. It all comes down to the cut surface.

The cut surface is the whole problem

A whole fruit or vegetable comes with its own packaging: the skin. Cut into it, and a moist surface lies open to the air. Two things happen. The moisture evaporates, so the lemon goes hard and the cucumber dry. And the oxygen gets in, and that is where the avocado turns brown.

Cling film shuts the air out, but it is used once and thrown away. A beeswax wrap does the same job. The sheet is cotton with beeswax and tree resin. It softens with the warmth of your hand, shapes itself around the food and holds that shape as it cools. Afterwards you wash it in cold water and use it again. There is more on that in the guide to using beeswax wraps.

How to wrap a cut surface in ten seconds

1. 1
   Pat the cut surface dry

   A clean cloth is enough. Surface water gives you condensation under the sheet.

2. 2
   Pick the right size

   S for half a lemon, half an onion and an avocado. M for half a cucumber and half a pepper. L is for whole bowls and larger leftovers.

3. 3
   Lay the sheet on the cut surface first

   Not over the whole thing. It is the cut that needs sealing.

4. 4
   Press down along the edge

   The wax softens as early as 35 to 40 degrees Celsius, which is simply the warmth of your hand.

5. 5
   Fold the rest around and hold it for a few seconds

   The sheet stiffens as it cools. Put the parcel in the fridge.

Avocado: why it turns brown

Avocado turns brown because an enzyme in the flesh reacts with oxygen. It is an ordinary chemical reaction, not a sign that the avocado has gone off. The layer is thin, and you scrape it away with a spoon.

Three things slow the reaction down, and they work best together.

• Leave the stone in the half you are saving. It only protects what it sits on. The rest you have to cover yourself.
• Rub a thin layer of lemon juice or olive oil over the cut surface. The acid slows the reaction, and the oil settles as a film.
• Lay the sheet straight onto the surface and press it right into the edge, so no pocket of air is left.

The half then keeps for one to two days in the fridge. Never rinse the cut surface under water. The water soaks in and turns the flesh soft.

Lemon, cucumber and pepper: the moisture has to stay in

Here the problem is the opposite of the avocado's. These lose moisture, and the cut surface goes first.

Half a lemon. With nothing around it, a lemon gets a dry crust within a day, and then you press almost no juice out of it. With the sheet held firmly against the cut surface it stays juicy for four to five days.

Half a cucumber. A cucumber is almost all water, and the open end goes soft first. Wrap the sheet around the cut end and leave the skin alone. The skin is already packaging enough.

Half a pepper. The seeds and the white membrane go off long before the pepper does. Cut them away at once, wipe the inside dry and wrap the sheet around it. Salad and herbs have tricks of their own, see the guide to keeping salad and herbs fresh.

The onion deserves a sheet of its own

Onion needs a rule of its own. When you cut into it, sulphur compounds are released. They are volatile, and they cling to fat. Beeswax is a fat, and that is why the sheet picks up the smell of onion so easily.

The fix is simple. Give the onion its own dedicated sheet, and use it only for onion and garlic. Then neither the butter nor the strawberries taste of onion next time.

Wrap the onion half with the cut surface well covered and put it in the fridge, ideally in a sealed box. It keeps for three to four days.

If the sheet has taken on a smell, hang it outside or by an open window for a few hours. Cold air takes most of it. The rest of the routine is in the guide to looking after beeswax wraps. The same principle applies to strong cheese, see the guide to cheese without plastic.

A quick overview, item by item

Covering a bowl of leftovers works a little differently. That is in the guide to covering bowls without cling film.

Frequently asked questions