When things go wrong, they keep going wrong...

[meganjane]

Andie, you're a gem!
I did use tomatoes, but tinned, which aren't terribly acidic. I use golden syrup and tomato sauce (ketchup), so all should have been good. They were different beans from a well known store called Loose Produce, so maybe they weren't as fresh as they should have been. The only different thing I did to the last lot that I made was that I didn't add any salt!!
I'll soak in salt next time. I'm wondering about the cooking method. Should beans be cooked slowly or can they stand higher heat?

[andiesenji]

Beans can be cooked at higher heat without harm, as long as you have plenty of water.  I know many people who cook beans in a pressure cooker, without pre-soaking them at all. 

There was extensive discussion on eGullet in 2007 about a method of cooking beans in the oven without soaking them.   
I've tried the method and it is okay but I still prefer the way I have been preparing them for the past nearly 60 years.

Here's the eG disucssion: http://forums.egullet.org/index.php?/topic/99104-no-soak-beans-in-the-oven-in-90-minutes/

Note that I posted about a "problem" I had with the water from my well, which is high in minerals, especially calcium.   Once I had a filtering system installed, I had no more problems with cooking anything and no build-up of mineral deposits in tea kettles, etc. 

One of the people who posted in that topic is "Rancho Gordo" whose name is actually Steve Sando.  He is a grower of heirloom beans and has been on TV shows demonstrating some of his cooking techniques.   
He has some terrific bean recipes on his site that should be easy to "convert" to metric.
http://www.ranchogordo.com/html/rg_cook_index.htm

Check out the "Drunken" beans.   I use milder peppers - the Serrano are a bit too spicy for me, but the beans are wonderful.
I've made it with black beans, white beans, calico beans, scarlet runners, etc.  all good!

[Thermomixer]

Thanks again Andie - great link and info.