Food safety wise, it isn't advised to reheat food in a slow cooker because it takes too long to reach a safe temperature. That period between 40-140 degrees, until heated through, is incubating bacteria. It's recommended to reheat quickly to reach 165 or above, using a m/w, stovetop, or oven. If you want to hold it, then you can transfer to the oven or slow cooker.

Edit: "...The average slow-cooker/crock pot cooks at approximately 200° F. on low and 300° F. on high. Bacteria thrive at temperatures below 140° F.; therefore, you want to be very careful not to do anything that might affect the cooking temperature and cause it to drop. In addition, most bacteria are killed at 165° F. So, as long as the lid is left on and the food is cooked for the proper time, and if the power does not go out, food will be safe to eat." - University of Florida IFAS Extension

I've looked into the cooking temps more and there's quite a range on how different brands/models seem to work. Some people on Chowhound have tested theirs and say that low/high is just a function of how long it takes to reach ~200, with that temp being the max.

When cooking a dish, I can recommend America's Test Kitchen's slow cooker books. See if your library has them.

I would first heat the beans up in the microwave . Then put them the crockpot and keep the temp turned to low to keep them warm all day. I actually do this often.

Uh-oh - I'll have to send instructions for a change of plans. Goes to show how little I know about crock pots. It would take way too long to heat in the microwave so I guess he'll have to transfer back to a dutch oven and heat in the oven. I was trying to avoid that because he's cooking something else in the oven and I thought it would get complicated for him trying to do two different things in the oven. I imagine the beans will take at least an hour to reheat in the oven - he can just serve them in the dutch oven.

Now I'm left wondering about the potluck events we used to have at our office. It sure seemed to me that people were heating their stuff up in their crockpots. I can't believe they all made the stuff in the morning before work and or reheated it in the morning. Well I never got sick - not sure about anyone else.

Teeda - I had a coworker who raved about her instapot and I thought maybe that would be a good time saver when I was busy. However now that I have more time I'm happy to keep cooking with good old pots and pans. I think dumping everything in an instapot would take away the joy of using my LeCreuset dutch oven - my favorite cooking instrument.

3katz, I don't have an electric IP but I do use a stove top one for a variety of things. They're great tools, time-savers, and sometimes they result in a superior product. They are also more energy efficient than oven cooking for hours. But, I get what you're saying. The only countertop appliances that see regular use are my coffee maker and combi-steam toaster oven!

Great for cheesecake and the steam helps prevent cracks. You just need a springform pan that fits inside (my pot is huge so a 9" fits).

The best for beans. I swear that they are infused with the aromatics when PCd

Wonderful for tough cuts of meats, while cutting time and energy use. My favorite is carnitas in the PC, and I reduce the liquid to pour over the meat.

I know that most people play fast and loose with food safety at cookouts and potlucks. Food is left out far longer than recommended, reheating from cold in a crock pot, etc. I'm fairly brave but I'd feel AWFUL if I knew better and someone got sick. Like the quote I included in my first post, it seems to be okay as long as the food has been at 165 for a bit. That should kill off everything that was growing as it came to temp.

I told him to heat in the oven in the dutch oven - he was fine with that. Better to be safe than sorry.

I have a slow cooker and although I don't use it frequently, for some food it is superb--I make chicken breasts that I then shred and freeze, black beans, spaghetti sauce, split pea soup etc.

Will an instant pot do all those types of foods? And what does it do well in addition? Now that we've moved I am seriously trying to consolidate/simplify all the STUFF in the house. Kitchen is particularly challenging because I've gone from a kitchen that I designed with tons of storage (and a huge pantry) to what is basically someone's HD weekend house kitchen with lousy storage and a single closet that serves as a food locker ;). I'll eventually remodel it but not for awhile so if there's something out there that will work as well as or better than the big ol cooker and take up less space, I'm all ears!

As an aside, I hosted a large gathering yesterday and had 3 slow cookers going with the same type/amount of food. I was surprised at how differently they heated.

Once the food is heated in the microwave, I would encourage you/him to keep them on the "warm" setting to avoid burning. You can always bump it up if needed, but baked beans could easily burn in a slow cooker.

running....yes, the Instant Pot will do all those kinds of food. I use mine mostly for different kinds of beans.

I haven’t had mine long but one thing I never heard before getting one is that they really are not big time savers for some types of food.

For instance when cooking chicken breasts, the IP needs to come to pressure (abt 12 minutes) then the cook time (7-11 minutes) then the release time (5-7 minutes). I can cook boneless chicken breasts on the grill faster. Just something to keep in mind.

An IP can be used to pressure, slow, and conventionally cook like steaming, sautéing, searing, yogurt making, and warming. I think it's a good tool to replace a traditional slow cooker if someone is looking to do that. It's also convenient for when you have other tasks waiting for you and you want a mostly hands-off experience. It's very handy for people living at high altitudes, as well.

I mentioned my go-to PC dishes, above, forgetting HB eggs. 6-6-6 is a method of cooking them on low pressure for 6 min, natural release for 6 min, place in cold water for 6 min, then peel. I find peeling the eggs MUCH easier after pressure cooking, compared to the stove-top method.

I also make stock.

Check out Hip Pressure Cooking and Seriouseats for discussions about pressure cooking, techniques, and recipes. Seriouseats is one of my favorite cooking sites and I like Kenjie's recipes.

Edit: Seriouseats has an article about why the flavor of foods don't develop as well in a slow cooker vs PC or oven braising.