Experimentbeginnerdraft
Green beans: green or grey?
Also searched as: chlorophyll experiment, vegetable colour experiment
In short: The same beans turn bright green or olive grey, depending on cooking time and acid.
Picture it
Like a spotlight that flares up and then fades: cooked briefly the green shines, cooked long it fades away.
Before · Afterraw
You need · 20 minutes
- a handful of green beans
- two pots of water
- lemon juice
- a bowl of iced water
Boiling water: only with adults.
How it’s done
Sequence · Step 1 of 4
Bring both pots to the boil; add a splash of lemon juice to one.
All steps as a list
- Bring both pots to the boil; add a splash of lemon juice to one.
- Divide the beans between both pots.
- After 2 minutes put a few beans from each into the iced water; cook the rest for 10 minutes more.
- Compare them all.
What you see
After 2 minutes the beans glow. After 10 minutes they are duller, and in the acidic pot clearly olive green.
Why it happens
Brief cooking drives air out of the tissue and the green glows. Longer cooking and acid turn the into an olive-brown pigment.
Sources
- Harold McGee: On Food and Cooking (2004)