Because of the condensation that collects in the slow cooker, flavours actually become diluted, not concentrated as you will often read. You need to add more herbs and spices than in conventional cooking to avoid insipid food. If your favourite conventional casserole recipe, for example, includes 1 crushed garlic clove, think about using 2–4 if you cook it in a slow cooker. I appreciate that sounds like an overpowering amount, but after a stew has simmered for eight hours the flavours will have mellowed.