Always boil vegetables on full power because if you turn the gas down, they take longer to cook.
Granny
Gas or electric, it doesn’t matter – the nub of this one is that Granny believes that if we reduce the power we use to boil a pot of spuds, they take longer to cook. Let’s find out.
Equipment used:
- One bag of potatoes of Tesco all purpose potatoes
- One bag of Tesco pasta
- One saucepan and its lid
- One electric cooker. We’ll use the same ring each time and allow it to cool completely between tests
- One rather fancy temperature probe so we can understand what’s the water temp. is doing
Now, for this high power level to cook something faster, it’d have to heat the water to a higher temperature (we can already see a flaw in Granny’s logic) but let’s give it a go and check. Potatoes in, lid on and away we go. Once we start to get bubbling water, we check the temp. and no surprise to find it’s showing just a shade under 100oC on the thermometer. Turning the power down so it’s simmering and we check again after five minutes: still a nice potato-cooking 98oC. We tried turning the power up to full but we had to remove the lid because it was jumping about so much (with potato in the water, the starches would cause a lidded pot to boil over anyway) and even with 5 minutes on max setting, the temp doesn’t rise above 100oC.
The fact is, tap water boils at approx 100oC and there’s absolutely nothing we can do to alter that unless we increase the pressure. By adding more energy we simply force more of it to vaporise per second – hence the lid-lifting enthusiasm we get – but the temp. remains steady at 98/99oC.
After the potatoes, we tried pasta and then carrots but came to the same conclusion: it seems the most energy efficient way to boil food is to bring it up to bubbling, put a lid on it (to reflect more of the escaping heat back in) and cook on the lowest gas/electric setting that kept it at the ‘just simmering’ point. Any additional power put into the equation is simply wasted energy.
Sorry Gran. Definitely not one of your hottest ideas!