ARC E-Newsletter 10/24/25: Turn Down Ratio

[Aprovecho Research Center]

Turn Down Ratio

One of the things that I like about the IWA Water Boiling Test is that it mimics the boiling and simmering functions of cooking food. Wood burning stoves are notorious for being too slow to boil big pots of water and for burning things like rice because they can’t be turned down enough to simmer.

At Aprovecho the farm, where we agreed to cook with wood, I ate a lot of burnt food! It was not always the fault of the stove.

Boiling and Simmering

How fast should a stove boil five liters of water? At ARC, we have a rule-of-thumb that if a stove takes longer than 25 minutes to boil five liters of water, people will usually not like it.

The IWA requires that a stove simmer water at between 97C and 93C for forty-five minutes. Rice cooks at those temperatures but it does not burn. It’s better to stay at the lower end of the range so tomato sauce does not taste smoky.

Nice to have guidelines when trying to make stoves. Of course, cooks in the project area may be a lot more specific and perhaps more exacting!

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