Has anyone ever used tomato paste from a tube? We use tomato paste with enough frequency to buy the pack of cans from Costco, but I hate having to either throw out a little or store a few tablespoons when recipes only use a little bit (and we do not use it so frequently that we need open containers in the fridge all the time). I've never seen tomato paste in a tube in my grocery store, but after seeing it at Williams Sonoma I found a few other sources online. Most of them require buying a fairly substantial quantity, so I'd love to hear what others' experience is. Many of these pastes are labeled as being "double concentrate." Do they really have twice the flavor? Am I right to assume you'd just use half the amount as a recipe calls for?