A query about dwarf yellow French beans

[Primrose]

How yellow are the beans and do they actually stay yellow once cooked? Having grown purple beans and found they turn green when cooked, I'm wondering how the yellow ones respond to the cooking process.

[Geoff]

It's a while since I have grown these as they are slug fodder with me. I last grew Rocdor and Serpedor (bought on holiday in France) and both were very yellow, stayed yellow and had an excellent flavour.

[glallotments]

We have grown yellow French beans and they do stay yellow - not a really bright yellow