You know those gorgeous, perfect-looking beefsteak tomatoes from the grocery store? They are liars. They look like they’d hold a salsa together, but they’re basically water balloons filled with tiny seeds. One chop and your cutting board turns into a swimming pool. Use them for salsa, and your guests will be slurping up a sad, pink gazpacho, wondering why they aren’t at a soup kitchen instead.
That’s your #1 enemy: the watery tomato. You need tomatoes with flesh, not just juice. You need tomatoes that have some guts, some substance, a tomato that is ready to stand up and be counted in a bowl of onions and cilantro. You need a tomato with structural integrity.