A precisely controlled bath has uses beyond cooking meat, and some of them carry their own cautions.
Infusions
Holding a liquid at a controlled temperature with aromatics extracts flavour without boiling off volatiles.
Syrups, oils and vinegars all take flavour readily this way in a sealed bag or jar.
It is faster and more controllable than leaving something on a windowsill for a fortnight.
The Botulism Caution
- Garlic and fresh herbs in oil are a documented botulism risk
- The organism grows without oxygen, which oil provides
- Heating does not destroy the spores
- So an infused oil must be refrigerated and used quickly
- Or acidified, which is what commercial products do
- Never stored sealed at room temperature
Equipment that holds a precise temperature, of the kind catalogued at https://everie.us.com/, makes infusion easy and does not make an unsafe storage method safe.
Yoghurt and Fermentation
A bath holds the warm temperature yoghurt culture needs far more steadily than an oven or an airing cupboard.
Follow a tested method for temperature and time. Clean equipment matters, since you are deliberately encouraging growth of one organism and not others.
Eggs and Custards
Protein sets at specific temperatures, which is exactly what a bath controls.
Custards, curds and confits all benefit, and the narrow windows are the appeal.
Tempering and Melting
Chocolate and butter hold at precise temperatures without a bain-marie.
Keep water out of chocolate, which seizes.
Reheating
Anything previously cooked and chilled, at its original temperature.
Follow Tested Recipes
Particularly for anything fermented or preserved.
Chill Everything Promptly
The rule does not change.
Refrigerate Infused Oils
And use them quickly, or acidify them.
Clean Equipment for Fermenting
Since you are encouraging growth deliberately.
Follow a Tested Method
Rather than adapting temperatures by feel.
Keep Water From Chocolate
Which seizes on contact.
Never Store Sealed at Room Temperature
Which is where the actual risk lives.
Label Anything Infused
With what is in it and when it was made.
Chill Everything Promptly
The rule applies to infusions exactly as it does to meat.