Julie Bove > wrote:

>"Steve Pope" > wrote in message

>> That's not my experience at all. Maximum has been about 70 minutes,
>> minimum 40 minutes (for common beans).

>Really?

>> I do tend to buy beans shortly before needing to cook them, maybe
>> that is part of the difference; I do not salt them until they're
>> nearly cooked, and then only minimally; but I suspect the biggest
>> difference here is tap water chemistry.

>That could be. We have really soft water here.

That could explain things.

Another possibility is if you're not boiling not vigorously enough
(or under some conditions too vigorously) it could take longer. There
needs to be boiling heat transfer into the interior of the beans.

Check this out:

http://en.wikipedia.org/wiki/Nucleat...cleate_boiling

If you look at the first diagram at the top of the page, there
is a region of inefficient heat transfer (the transition region).
Paradoxically, in this region, turning up the burner
will result in less heat transfer.

Personally I put a lid on the pot, but cracked open about 1/4"; and
set the burner so that the pot just barely doesn't boil over.
So a fairly vigorous boil.

Steve