Originally Posted by Michael in FtW
How much a fryer will loose temp depends on the initial temp of the oil and how much stuff you add to it. How quickly it will recover depends on the heating element(s) ... an immersion system works best.
It would also depend on the temperature of whatever you are frying. Frozen french fries, for example, will not only cause a termendous agitation of the oil, they will also reduce the temperature of the oil. I have gotten into the habit of taking anything I will be deep frying out of the refrigerator or freezer at least an hour before I plan on cooking it.
I have a Philips HD6161 Digital Professional Fryer, which I bought at Target, but I believe they are no longer available in the United States, but are still available in Europe. It holds approximately 4 quarts of oil to the fill line. I've had it for about 5 years now, and it is an excellent product.