Are you packing? School lunches, I mean. Check out today’s Food section for Sally Sampson’s tips on how to bag a lunch your kids with eat, plus her great ideas for lunchbox upgrades.

Also today, Tim Carman writes about a local law firm that advocates for food truck owners in localities where they’re being threatened by new regulations. And Gastronomer Andreas Viestad tells how you, too, can make your own yogurt without using any special equipment.

And finally, don’t forget today’s Free Range chat. Tune in at noon and settle back for a lively hour of Q&A with the Food folks. You can just lurk and enjoy, or you can bring a question for us to answer. Here’s one we didn’t have time for from a previous chat:

Are there any concerns with changing the temperature on a slow-cooker recipe and adjusting the time? I’ve read that one hour on high equals two hours on low. Sometimes I want to shorten an all-day/low-temp recipe, or stretch out the cooking time for a quick/high-temp recipe.

Slow-cooking can be a flexible and forgiving medium, within limits, and many times you will be able to fiddle with timing and temperatures and still get good results. But not all the time.

There are caveats. Tougher cuts of meat really benefit from the tenderizing, flavorizing effects of slow-cooking, so trying to hurry them through the process would be a mistake. Pot roasts, chuck, round steak and brisket, for example, do best on low heat for long periods of time — unless you like your meat chewy. On the other hand, poultry and chops require relatively short cooking times and might not take kindly to a long stay in the heat. Seafood, too, would be a poor choice for prolonged cooking; it would either disintegrate or become rubbery. Bean dishes, cooked too long, can turn mushy.

The makers of the Crock-Pot have a simple chart on their Web site that shows how to convert cooking times between high and low. The time difference is more than double at the low end — food that calls for three hours on high needs seven hours on low — but the gap narrows at the high end: Food that calls for eight hours on high needs 12 hours on low. So there’s not one basic ratio you can use. The site advises not trying to convert recipes whose cooking times are less than three hours on high or seven hours on low. Aside from that, according to Crock-Pot, “most dishes can be prepared on either high or low.”

Slow-cooker temperatures vary among brands, so as with many things in the kitchen, there’ll be a certain amount of trial and error, but if you follow a few basic guidelines, you should be fine.