-Hello everyone,
Yesterday I was preparing some tomato sauce and, in order to remove some water from the sauce, I put it in a pot on the burner and waited until it started to evaporate. When I sow a steady quantity of vapor coming out of the pot I started to blow on it in order to remove some vapor and let the new one create. Is blowing on the pot lowering the time the water needs to evaporate because the already created vapor 'get out of the way' faster or is it enlarging the time because the "cool" air is lowering the temperature of the water/sauce in the pot?
To summarize the question:
Is blowing constantly over a pot with some watery food in it making a difference in time the water needs to evaporate?
and
In the case of the sauce, blowing on it lower or enlarge the time the water needs to evaporate?
This question is more related to physics of liquids instead of how to properly cook a sauce.
Please feel free to update the title and/or the tags if necessary
Update:
The sauce was at (water) boiling temperature. On the top of the sauce bubbles created from boiling was visible.
Assuming that blowing on the pot lower the time the water takes to evaporate obviously there is a "limit" on how much you can blow on the pot before the quantity of the air blown starts to cool the sauce instead of only removing the vapor. How can I try to determine that amount of air?
Best Answer
Blowing on the pot will significantly increase the evaporation of vapor.
When the sauce boils, it means that vapor bubbles are forming throughout the pot, rising to the top. Blowing may slightly lower the temperature on the surface, but it will not influence the boiling throughout the pot.
On the other hand, the rate of evaporation is determined by the relative humidity of the air above the pot, to put it simply (more technical: the gradient of chemical potential). Blowing on the pot replaces the vapor-saturated (high-humidity) air with air that can take up water vapor (technical: you maintain a large gradient in chemical potential).