When to Add Tomatoes or Vinegar to Dried Beans

For your next pot of dried beans, prepare the tomato mixture separately and combine it with the beans once they are fully cooked and soft. Leave vinegar until this stage too. This is cautious cooking advice, rather than a tested promise of a particular time saving.

In a 2022 study, Justice Munthali and colleagues examined eight common-bean varieties, with both soaked and unsoaked treatments. One of the cooking waters contained 1% citric acid. Cooking took longer in this acidulated water than in the tap and borehole waters used in the study. The tested result concerns that cooking environment; it does not establish that beans can never soften in acid.

The distinction matters in the kitchen: the researchers did not directly compare adding tomatoes or vinegar early versus late. In their discussion, they advised adding acidic ingredients when beans are fully done, citing earlier guidance. That advice is consistent with their acidulated-water finding, but is not itself the result of a timing experiment.

Use the beans’ cooked texture as the cue for combining them with the tomato mixture, rather than a fixed number of minutes from this study. How much time this order might save in your recipe is unknown. The finding does not establish the same effect for every bean variety, legume or recipe. No recipe test was carried out for this article.