Why Do My Red Onions No Longer Turn Pink In The Greek Salad

Asked by glinys. Answered on 22nd March 2023

Full question

I have made Nigella's Greek Salad many times but suddenly the onions don't turn puce and translucent after marinating in red wine vinegar and oil as per the recipe. I used a fresh bottle of vinegar.

The Ultimate Greek Salad — Photo by Petrina Tinslay

Greek Salad, My Way

By Nigella

Our answer

NIgella's Greek Salad, My Way (from NIGELLA SUMMER) has a traditional combination of feta, tomatoes and olives that are dressed with red onions steeped in vinegar. Soaking the onions in red wine vinegar helps to soften them and also mellow their flavour slightlty.

Usually when you mix sliced red onions with an acid, such as vinegar or citrus juice, they turn bright pink. Molecules in the red onions called anthocyanins react with the acid to cause the colour change. We were wondering if the oil was mixed in with the onions before the vinegar, as the oil could have formed a liquid-repelling coat on the onions before the vinegar could act. It may help to just toss the onions with the vinegar first, let them stand and then stir in the oil just before you use the onions in the salad.