The article has an egregious typo where they say “The pot containing a 20% salt concentration will heat up over 25 times faster”. I think they meant “over 25% faster”, which is either true or close-to-true. I’m not sure about the conclusion that cooking time goes (slightly) down; I think they’re holding total-mass fixed, but if we’re talking about “adding salt” then we should hold water-mass fixed instead, which adds onto the boiling point elevation effect and might tip the balance. I didn’t do the calculation because it’s entirely pointless. :-P
The graphs look like straight lines within the range from 0-5% salt concentration, so I’ll use the numbers at 5% and assume they scale down to the epsilon of salt one would actually add.
Density appears to increase by 4%.
Specific heat appears to go from 4200 to 3930 (edit: not 3850, whoops), a decrease of ~7%.
Boiling point … not present in your link, but this says approximately +0.5° C per 2.9% of salt, so let’s say at 5% salt it becomes 100.8°C. The delta from a starting point of, say, 21°C thus increases by about 1%.
Conclusion: time to boiling is multiplied by 1.04∗.93∗1.01=0.98, a (tiny) decrease.
Addendum: I see recommendations of 1 tablespoon of salt per gallon of water, which is 0.4% by mass, so in practice the time to boiling would be multiplied by more like 0.998.
I think you meant 3950 not 3850? And if we hold water-mass fixed instead of total-volume (i.e. the water is already in the pot and we’re deciding whether to add salt or not) we should use 5% not 4% (density doesn’t matter, because we don’t care whether the volume goes up a bit upon adding salt). Seems awfully close to even.
The article has an egregious typo where they say “The pot containing a 20% salt concentration will heat up over 25 times faster”. I think they meant “over 25% faster”, which is either true or close-to-true. I’m not sure about the conclusion that cooking time goes (slightly) down; I think they’re holding total-mass fixed, but if we’re talking about “adding salt” then we should hold water-mass fixed instead, which adds onto the boiling point elevation effect and might tip the balance. I didn’t do the calculation because it’s entirely pointless. :-P
Doing the math because I have the urge:
The graphs look like straight lines within the range from 0-5% salt concentration, so I’ll use the numbers at 5% and assume they scale down to the epsilon of salt one would actually add.
Density appears to increase by 4%.
Specific heat appears to go from 4200 to 3930 (edit: not 3850, whoops), a decrease of ~7%.
Boiling point … not present in your link, but this says approximately +0.5° C per 2.9% of salt, so let’s say at 5% salt it becomes 100.8°C. The delta from a starting point of, say, 21°C thus increases by about 1%.
Conclusion: time to boiling is multiplied by 1.04∗.93∗1.01=0.98, a (tiny) decrease.
Addendum: I see recommendations of 1 tablespoon of salt per gallon of water, which is 0.4% by mass, so in practice the time to boiling would be multiplied by more like 0.998.
I think you meant 3950 not 3850? And if we hold water-mass fixed instead of total-volume (i.e. the water is already in the pot and we’re deciding whether to add salt or not) we should use 5% not 4% (density doesn’t matter, because we don’t care whether the volume goes up a bit upon adding salt). Seems awfully close to even.