S. Heisley wrote:Add salt?
I recently saw that adding salt to your ice chest water before freezing it will keep food colder longer. (The article didn't say how much to add.) Has anybody tried it? What's the ratio of salt that should be added?
Common misconception. Adding salt lowers the freezing point of ice, not the temperature itself. So if you add X amount of salt to some water, it won't freeze until it's 29 degrees, for example. That's why they salt the roads in winter. The salt reacts with the ice and snow, lowering the freezing point (which of course is also the melting point when the temperature is going up). That helps the ice melt quicker and clear the roads. That's also why they don't salt once the temperature gets too low. The salt can only lower the melting point so much.
I think the "add salt" idea comes from the homemade ice cream crowd. You DO add rock salt to your ice when you're making ice cream, but that's just to allow the water from the melting ice to stay below 32 degrees. The churn turns easier in water than ice, of course, so you turn the churn more easily, yet keep it below freezing.
After years and years of camping, ice cream making, picnics and parties, here are the best ways I've learned to keep ice longer:
1. Do NOT break up the bags when you get them. Yes, it will cool your beer, etc FASTER when you break it up, but that's because it is losing it's coldness faster to whatever is in the cooler. In other words, it's melting faster. That's because breaking it up gives it more surface area. Breaking it is good for parties, not so good for food and camping. That's why ice for ice boxes was always delivered in big blocks back in the old days.
2. Frozen is frozen, but your deep freeze will give you ice at zero degrees generally, so it will stay cold a lot longer. Depending on your settings, your refrigerator's freezer is probably just a few degrees below 32. The ice machine at the gas station/campground/etc is at 31 or so. Why? Cheaper to keep the temp higher, and of course you'll need ice sooner if it melts faster.
3. Keep your cooler in the shadiest spot you can find. The temp is what it is outside, but of course we all know it feels cooler in the shade. Your ice will feel the same way.
4. Open it as little as possible. Every time you open it, you're letting in warm air. So if you're getting stuff out for dinner, get it all out at once.
5. Use one of those cooler covers. Yes, those silly looking foil bubble-wrap contraptions. They really do work (especially out in the sun), even if they aren't the highest quality. ANY kind of insulation helps. On the boat we sometimes wrap our towels around and over the cooler, for example.
6. Don't drain the water. I know some of you won't agree, but I've done lots of unscientific testing on this. As long as the food, drinks and new ice fit in the cooler still, I never drain the water. Its mass holds the cold better than air. In other words, if your cooler is nearing empty on food or drinks and you keep the water drained, that's just more air in there. Then when you open it, warm air goes in. If you keep the water in there, that's less warm air coming in (same principle as the ice cream churn I mentioned above). This is also why keeping frozen jugs of water in your deep freeze is a good idea if have empty space. That and the fact if you lose power, you have all that mass keeping your food cold.
by Cosmo » Tue Jul 19, 2016 7:55 pm 
