How do I choose a slow cooker?

Slow cookers are simple appliances and most of them cook similarly. The differences that matter are the size relative to the fill rule, whether you can brown in the pot itself, and whether the lid and the pot are things you will happily wash. Digital timers and programmes matter far less than any of those.

Step by step

1. Size against the fill rule, not the headline litres.A slow cooker should be between a third and two-thirds full to cook properly. Under a third and the food dries and catches; over two-thirds and it will not reach temperature safely. So a 6.5 litre model used for a two-person stew is worse than a 3.5 litre one.
2. Match capacity to the household.Roughly: 1.5 to 2.5 litres for one person or side dishes; 3.5 litres for two to four; 5 to 6.5 litres for five or more, for batch cooking, or for anything that has to hold a whole joint or a chicken.
3. Look hard for a hob-safe or searing insert.The single most useful feature. A metal insert you can brown meat and soften onions in directly, on the hob or on a built-in searing element, removes the extra frying pan and the extra washing up — which is the reason the browning step gets skipped and the reason slow cooker food often tastes flat.
4. Decide between ceramic and metal pots on how you will use it.Ceramic holds heat well, is heavy, and cannot go on a hob. Aluminium or steel is lighter, can usually sear, and cools faster. Ceramic also chips and cracks if thermally shocked, which is a real failure mode when someone fills a hot pot with cold water.
5. Check the lid.A heavy glass lid that seals well is what keeps the moisture in. A loose or lightweight lid lets steam escape and dries the dish. Some have a locking or clip-down lid, which matters if you transport food.
6. Decide whether you need a timer.A digital timer that switches to keep-warm at the end is genuinely useful if you cook while out. A simple low-high-warm dial is otherwise perfectly adequate, cheaper and has less to fail. Keep-warm is not a cooking setting and food should not sit in it for hours.
7. Check the pot and lid are dishwasher-safe, and that you can lift them.A full 6.5 litre ceramic pot is heavy and hot. If you will be lifting it out to serve or to wash, handle it in the shop. This is the reason large ceramic models get used less than their owners intended.
8. Note the wattage for the running-cost comparison.Typical slow cookers draw 150 to 250W. Eight hours is roughly 1.2 to 2.0 kWh, so at an example rate of 25p per kWh that is 30 to 50p for a whole day's cooking. It is one of the cheapest ways to cook there is.

Tips

• A slow cooker that is too big for most of what you cook is a worse buy than one that is slightly small. The fill rule is the constraint, not the maximum.
• If you cannot find a hob-safe insert at your budget, a slow cooker plus a frying pan you already own is fine. Just accept that the browning step is not optional if you want depth of flavour.
• Multi-cookers combine slow cooking with pressure cooking and sautéing. They do slow cooking adequately rather than excellently, and they are worth considering if worktop space is the binding constraint.
• Buy a spare sealing ring for anything with a gasket at the same time as the appliance. They perish and they are the part that is discontinued first.

Common mistakes

• Buying the largest one for the same price — A large pot cooking a small quantity dries, catches at the edges and cooks unevenly. The fill rule means capacity has to match the usual portion, not the biggest one.
• Assuming the keep-warm setting is a cooking setting — It holds food above the danger zone but it is not cooking, and food held there for hours degrades badly. Use the timer to finish cooking near serving time instead.

Alternatives

• Basic dial slow cooker, ceramic pot: Cheapest and most reliable. Low, high and warm, a heavy pot and a glass lid. Does the job perfectly if you do not mind a separate frying pan.
• Slow cooker with a hob-safe searing insert: Brown and soften in the pot itself, then slow cook in it. Removes the extra pan and the extra washing up, which is what makes the browning step actually happen.
• Digital slow cooker with timer and auto keep-warm: Set a duration and it switches to warm at the end. Worth it if you cook while out; otherwise a dial does the same job with less to go wrong.
• Multi-cooker: Pressure cooking, slow cooking and sautéing in one unit. Saves worktop; does each job adequately rather than excellently, and is more complex to clean.

Questions people ask