I'm currently making 9 litres of quite thick lentil soup in a 10 litre stainless steel stockpot. It needs to simmer gently for an hour or two. Despite the sandwich base and my weakest gas ring on minimum*, it needs stirring every few minutes or it will stick, and soon burn.

I've found this with other similar soups too (e.g. split pea and ginger) and dal. What they have in common is that they're too thick to convect properly. Today's is worse because I'm making it extra thick thicker for further dilution to serve about 40 people. Small batches can be done n my 3.5 litre slow cooker, though even in that it can stick.

Because this cooks for quite a long time, I need to be able to get on with other things, not all in the kitchen. So I wondered about solutions for automated stirring. In small vessels in the lab, for example, there are magnetic stirrers built in to hotplates. Is there something larger for use at home, whether a product (perhaps something that could be repurposed), a DIY design, or something I haven't considered.

* I have a flame diffuser, but it's a bit small for the pan and couldn't be trusted to take the weight. A diffuser that clipped under the pan supports would be interesting, like the wire gauze sometimes used with bunsen burners.

  • I tried the flame diffuser wedged between the burner and pot support, but it's too big to fit centrally and after a few minutes the wooden handle started to scorch where it touched the metal.
    – Chris H
    Commented Apr 7, 2022 at 12:53
  • Someone should come up with some sort of immersion circulator for thick liquids...
    – Luciano
    Commented Apr 7, 2022 at 14:15
  • 1
    You could probably rig a paint stirrer, clamp-stand and electric drill. Trick would be to get the drill going slow enough to stir without creating a soup tornado.
    – bob1
    Commented Apr 7, 2022 at 22:47
  • 4
    I have fantasized about using a magnetic lab stirrer in the kitchen for most of my adult life.
    – Tom
    Commented Apr 8, 2022 at 1:28
  • Not quite the answer, so I won't post it as such, but I regularly cook (very) thick soups, at least on the level of Dal soups, and have zero issues with burning in. I usually let them simmer for 20-30 minutes with no attention of mine at all. This is in stainless steel pots (I cannot exactly tell you what material or coating they have - if there is any, it's not visible and does not go away after decades of use, so I assume it's just stainless) on an induction stove. Maybe add the material/type of your pot, maybe that helps people come up with even better answers.
    – AnoE
    Commented Apr 8, 2022 at 10:31

4 Answers 4


When I am cooking very thick soups I often put the pot in the oven instead of the stove and cook it that way. Because the heat is distributed around the entire surface I don't run into problems of it burning and sticking. Be sure to manage the temperature though, just around boiling is good.

  • 3
    I thought about that, but was sure this pot didn't fit. Prompted by your answer, I had another check. It just fits if I put the shelf on the floor of the oven instead of where it's supposed to go
    – Chris H
    Commented Apr 7, 2022 at 12:42
  • 1
    There's nothing wrong with that as long as the pot is rated for the oven temperature. You don't want it resting directly on the oven floor, but having the grate in between should be fine.
    – GdD
    Commented Apr 7, 2022 at 12:44
  • I don't honestly know about the handles (it's a cheap ikea one) but as I can set 100--110°C for the oven and put the pan in hot they should be fine as handles can get that hot on the hob.
    – Chris H
    Commented Apr 7, 2022 at 12:48
  • Yeah, that's a safe assumption.
    – GdD
    Commented Apr 7, 2022 at 12:53
  • 15
    That turned out to be the solution I really needed. I might cook in metric but I now have 2 imperial gallons of slightly concentrated soup cooling in the fridge to fuel a bunch of hungry cyclists on Saturday (and I've just worked out that apparently fuelled by hearty soup a cyclist gets about 54 miles per gallon)
    – Chris H
    Commented Apr 7, 2022 at 16:50

I thought we had a question about this some time ago, but I can't locate it. Google or Amazon search "auto stirrer for kitchen." Here is one example. Plug it in. It stirs for you. Not sure how thick is too thick for these, so maybe someone with personal experience can comment.

Given the discussion, I will just point out that there are other designs.

  • Having seen a video it appears to work by stick-slipping against the base of the pan, and vibrating its way round. So I suspect it's not going to work in my case. Also the legs are far too short - the battery case would barely stick out of my soup, and "Never leave device unattended" rather defeats the object. But it's good to know that things exist
    – Chris H
    Commented Apr 7, 2022 at 12:46
  • 2
    The never leave it unattended sounds like a legal protection thing to me, if you leave your pot unattended and your house burns down you can't point the finger at them.
    – GdD
    Commented Apr 7, 2022 at 12:52
  • 1
    I used to have a device of this type. As far as I can remember, it did work - not perfectly, but it was good for things like puddings thickened with egg yolk or starch, it prevented that thick overcooked or burned layer on the bottom. It is too small though, because only the legs are allowed to be immersed in liquid, the whole case has to be above. Also, mine broke down even though it hadn't been used too much, and I didn't feel like it added enough value to be replaced.
    – rumtscho
    Commented Apr 7, 2022 at 12:57
  • 1
    @rumtscho a big red flag to me is that while it's clearly only immersible up to the top of the legs, that crucial dimension isn't specified . Even if the product is fit for purpose, the marketing isn't.
    – Chris H
    Commented Apr 7, 2022 at 13:03
  • 1
    This design might work better for thicker soups, as it can be adjusted to get into the corner and scrape the bottom of a large range of pot sizes: smile.amazon.com/…
    – Joe
    Commented Apr 7, 2022 at 14:47

If you're after DIY and don't mind some dilution, then Direct Steam Injection (DSI) might be your answer. In a domestic environment you could get your steam from the top of a pressure cooker using a hose and your soup pot could be insulated. The bubbles of steam both transfer heat and, rising, stir your soup.
DSI is a used in industrial scale food processing, as evidenced by this university course although generally in a continuous process (in pipes).


There are also products on the market named "soup makers" which has as one of it's features: no need to stir

E.g. https://www.philips.nl/c-m-ho/koken/soupmaker-topic

enter image description here

This picture from a different one shows the stirring part

enter image description here

  • 7
    The asker is trying to work with large batches (9 liters in a 10 liter pot), which is part of the problem they are trying to solve. Not sure a 1.2 liter device would help much?
    – Stephie
    Commented Apr 8, 2022 at 9:16

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