Bitterness is a common complaint when most anything begins to bolt though some notice it far more than others do. Plants in the process of bolting have very distinct characteristics - prolongation of the stem being one of the most obvious - but "pointed leaves" may simply be a varietal characteristic.

Dave

I think it is known that pointed leaves in spinach is something that spinach does when it is about to bolt, and Dave's point about bitterness pertains. So I think both of your theories are right on.

Ok I agree. Spinach I planted last fall is already starting to bolt which seemed fast.

I’d love to know what happens if you cut off the pointed leaves, then fertilize and irrigate generously.

You hadn't indicated in your original post that this was a year old crop. Obviously that makes a difference given it is a biennial crop. However there are varieties of the flat/smooth leaf spinach that do have pointed leaves that are NOT bolting. The smooth leaf Arrowhead varieties like Catalina, Indian Head, Space, and New Zealand come to mind.

Serun - once bolting is triggered in the plant by either age or heat you really can't stop it.

Dave