Thinking about cauldrons, I've got an idea to divide water (a resource) into subtypes somewhat alike states of a juice. In most basic form it could be 3 types: "Hot water", "Water"(not a generic one, but "Warm water" sounds a bit off and overly verbose for me.. I'll call it "Normal water" here), and "Cold water". I'm not a native English speaker, so maybe somebody could suggest better names... By "hot" I mean something closer to "boiling hot" like one that is used for tea, and by "cold" I mean "freezing cold".
Different recipes may require a specific kind of water, or a generic one, or have different outcomes for different kinds of water. Like FEP variations.
These types decay into each other, but a bit differently in different circumstances. During 3 of 4 seasons and inside houses it is hot -> normal <- cold, while in winter it is hot -> normal -> cold. Also, all river, lake, etc. water is normal during 3 seasons and cold in winter. Or maybe put the boundary somewhere at mid-spring and mid-autumn. Wells... IDK, maybe they should produce different types depending on depth, but I'm not sure whether they should always allow to get "cold water" if dug deep enough.
One of the main points is cauldrons that would produce real "hot water" and would serve as a storage, so you can "open" it and craft something with hot water like you craft with a resource from a barrel. When filled with cold water, a heated cauldron would turn it into normal first. I can't think of many other sources of hot water besides trivial hot springs. These springs (and pools) may appear in caves as well.
Other springs perhaps should be mostly cold water, including "Headwaters". Ice decays into cold water as well, of course. Perhaps ice should be treated a bit like an additional type of water, so it could be stored in vessels and containers for liquids (to decay there into water, yep).
This way it would be a task to get cold water in warmer seasons (haul a cube of ice or snow from mountains before it warms up all the way to "normal water"), and maybe a need to change a source to get normal water in winter. Ah, and the water could lose a bit of Q each time it changes type. Something like 10%-20%? So there would be a reason to use a natural hot water source instead of simple boiling, a reason to seek cold springs instead of melting ice. Also a reason not to repeatedly boil and cool down water in cauldron.
I suppose, this scale of water can be further extended to something like:
"Boiling water"
"Hot water"
"Warm water" (equals to most cases of "normal water" in the text; no need to abstain from "warm" if there could be "cold" which does not mean "freezing cold")
"Cold water"
"Freezing water" (equals to "cold water" in the main text)
"Ice"
- if needed. No need for "steam", I suppose, as we aren't Minecraft...