Sous-vide green beans – temperature?

The following question has been received:

“At home we eat a lot of vegetables and it’s good to have them always ready. To ensure this, I bought a sous-vide cooker. I tried cooking green beans from a local grower, and I used both a temperature of 85°C for 30 minutes and a temperature of 88°C for 30 minutes, the result is always the same… too raw. Where am I going wrong?

This was our chef’s answer:

“Hello,

I recommend that you cook them at 90°C-95ºC, as green beans have a large amount of cellulose and require cooking closer to boiling point. It’s not clear to me whether you’re cooking the beans directly in water or if you put them in bags. Either way, cooking at the indicated temperatures will give you a better result.”

Thank you,”