I've been buying good lettuce recently and have been storing them in the fridge in a water bath. This way the lettuce stays in good shape and I prepare some salads. After about a week, however, the lettuce becomes inedible because of the bitter taste.

Do you know why this happens or any way to prevent the bitterness?

4 Answers 4


I think the key here is that you've been buying oversized lettuces. Bitterness of lettuce plants is not something under your control. When the lettuce matures (on the plant), it eventually starts flowering (called "bolting") as a way to perpetuate its genes. Once this sets in, the leaves turn bitter due to the production of certain chemicals, and acts as a defense mechanism against insects.

The process of bolting is irreversible and if it has commenced in the plant, it will continue on in the cut lettuce head (perhaps at a diminished rate). Big lettuce heads are invariably more mature than the smaller ones, which is why you experience a higher occurrence of them turning bitter. You could try the other suggestions here, but I cannot say for/against any of them as I haven't heard of any of them being used to control bitterness.

My advice would be to buy small to medium sized lettuces. Young leaves are tender and less likely to turn bitter. One might be tempted to buy the biggest lettuce on the shelf so as to "maximize" the leaves/dollar, but in the end, you have to decide whether the bitterness is really worth it.


I expect that the ultimate answer to your question is to eat your lettuce faster and restock sooner. I fear getting more than a week of "freshness" out of your lettuce may be expecting too much. Since you are storing it in a water bath, you can get an extra couple of days out of raising the acidity of your bath a bit. Try adding a little bit of lemon juice to water (1 tsp).

  • I'll give that a try (the lemon juice). Eating faster is a bigger problem as these are BIG lettuce. Aug 24, 2011 at 16:24

Remember to never cut lettuce with a metal knife. It will oxidize the lettuce and possibly create that bitterness. They sell plastic lettuce knives, but I used to work in the produce dept of a grocery store and our favorite lettuce knife was to get a plastic cake cutter (cheap/free) from the bakery dept.


This is a partial answer dealing with only one type of lettuce: There is no way I know of or have heard of to remove the bitterness in iceberg lettuce. There is a way however to avoid buying a bitter head of lettuce, which I practice:

When shopping for lettuce, I take use my thumbnail to make a wide scratch at the cut stem and smell it (use anything to make the scratch - the idea is to expose fresh unexposed cells). Bitter lettuce is detectable by smell and can be rejected.

I have rejected whole bins of iceberg lettuce in the USA as bitter and used alternative types.

In the USA, the lettuce is now mostly wrapped in plastic at the grocery, requiring the peeling back of the plastic to scratch the stem.

  • Could you explain what you smell? Aug 21, 2011 at 13:40
  • 1
    Is a bit difficult to describe, to my nose, the bitter lettuce has a strongish, slightly bitter smell, while the sweet lettuce has very little smell. The best thing is to start smelling, and tasting. These tried and true methods work for many things. I've gotten weird looks a few times for biting off the end of a carrot to check flavor before purchasing large bunches. Decades ago the green grocer would have the various viands out for sampling. Some grocers would even cut a small wedge out of a watermelon they selected, to allow tasting. A thing mostly of the past now, unfortunately.
    – Frankie
    Aug 24, 2011 at 0:22
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    At any rate, the question is how to prevent bitterness from building up. The lettuce started out perfectly. Aug 24, 2011 at 6:16

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