Denatured vs Isopropyl Alcohol for Fondue Pot
I'm not sure if this is the right board for this question, but here goes. I just bought a fondue pot that takes denatured alcohol for the flame. I've seen various posts saying that you can substitute isopropyl alcohol instead, but the postings didn't seem too credible. Does anyone know if I can substitute the isopropyl alcohol for denatured? I'd rather not burn the house down.
We're talking about different percentages of water included in the product.
Denatured alcohol starts with consumable (ethyl) alcohol & then has "de-naturing" compounds added (menthol, isopropanol, gasoline!?) to prevent people from drinking it. It's usually a low percentage of water (5%or less), so it burns easily.
Isopropyl alcohol is usually sold as "rubbing alcohol, 70%" (for skin application), which means it's got more water added (30%) to keep from excessively drying out the skin. You can find isopropyl with less water added, but I've noticed it's getting more dilute lately. A few years ago you could get 97% isopropyl at chain drug stores. Then it was 95%, & now it's down to 92%-91%. 30% water is difficult to start burning (although, we routinely observe 80 proof brandy (60% water) being lit on flambes). I don't know how difficult 8% or 9% water is to get started, or if it will burn cleanly or not. If it's cheaper & easier to find than denatured, I'd certainly give it a try.
We've been using denatured in fondue pots for 40 years or so, and that's what I'd recommend. The typical isopropyl sold in drugstores as rubbing alcohol is about 30% water - it'll work in a pinch, but denatured really is better. As Whats_For_Dinner suggested, a higher concentration of isopropyl will work fine (maybe better), but is less commonly available, and with denatured so ubiquitous I don't think the straight isopropyl is really worth searching for.
Assuming you can get 99% isopropanol, I'd use that over denatured. Denatured, by nature (apologies for the "pun") contains all sorts of other stuff that I'd rather not set on fire in a non-lab setting. ;)
Not sure of the availability of high% isopropanol where you are, though. If all you can get is the 70%, I'd use the denatured.
It's been about 13 years since my last organic chemistry class, but most alcohols are all the same thing except for chain length (#of carbon atoms), which affects burn temp and rate. For the most part they are all interchangeable because the difference is only a few degrees. But like scott said, they will also produce different "leftovers" that may harm the unit. So in affect, I don't think I answered your question.