We bought dried kidney beans for a canned-bean slow-cooker recipe. How do we change the plan without an argument?
FoodMy partner tipped the shopping onto the counter and said, "These were cheaper." He'd bought dried red kidney beans for a recipe specifying two cans, drained. We were going to put the ingredients into the slow cooker before going out.
I hadn't started cooking. Looking up the substitution led me to the [Food Standards Agency's advice on raw kidney beans](https://www.gov.uk/government/publications/home-food-fact-checker/home-food-fact-checker): raw or undercooked red kidney beans can contain a harmful lectin, and they should not be cooked raw in a slow cooker. Canned beans have already been processed with soaking and boiling.
We'll get the canned beans for this recipe rather than improvise a dried-bean conversion today. My partner thinks that defeats the point of planning a cheap, convenient meal, and says I treat every small change like an exam. How would you explain why this substitution changes the preparation, without turning a missed line on the shopping list into a judgment on his cooking?