Recollections with Richard Bleil
Back in the ‘80’s, a national “Mexican” restaurant that is no longer in business here in the US (although, as I understand it, it is in other countries, but wouldn’t it be hilarious if it was Mexico?) was the first one to offer Fried Ice Cream. I say “Mexican” because, like so many restaurants in this country, it is more of a Tex-Mex food, as opposed to authentic Mexican restaurant.
Anyway, it’s not clear what the actual origin of Fried Ice Cream actually is, but this was the first restaurant to offer it as a menu item. A few days ago, I found myself in a different “Mexican” franchise restaurant and saw that they offered Fried Ice Cream. Recently, the “Fried Ice Cream” I’ve been finding is kind of a non-fried knock-off of the true Fried Ice Cream. It’s usually covered in some kind of flakes not unlike a cereal, with maybe chocolate or honey or some such thing. It’s very good. I do like it, but it’s like the “no-back” cheesecake. Yes, it’s delicious, but it’s not the real thing. By the way, one of the most interesting knock-off version of fried ice cream had raisins in it, which, having been frozen, were very chewy and was an interesting addition.
True Fried Ice Cream is actually fried. This sounds counter intuitive, as you can’t keep ice cream frozen in hot oil. Or can you?
The way that it works is to start with ice cream balls. They are frozen in a particularly cold deep freeze. They are then coated in fry batter, and deep fried. It’s a delicate balance, though, and the people who do it have to practice. My friend in High School used to make these and burned himself on the hot oil in this practice (not very bad; he was fine, just in a lot of pain) and explained it to me even then. You have to dip it long enough to fry the coating, but not melt the ice cream. So, you dip these extremely cold ice cream balls into the fry oil, just long enough, and very quickly flip it back into the freezer. If you don’t leave it in the oil long enough, nothing happens with the coating, but leave it into long and you get mush.
This is a fascinating study in the difference between kinetics and thermodynamics. The browning is caused by “pyrolysis”, which basically means oxidizing, or burning. In meats, it’s the proteins, but in delicious deserts, it’s the sugars that are oxidized causing them to undergo “caramelization”. This caramelization first breaks down complex carbohydrates into simple sugars, then forming new chemicals such as maltol (toast like flavor), furan (nutty flavor), diacetal (buttery flavor) and ethyl acetate (fruity flavor). This process also drives off water, making the sugar thicker and more viscous (slow moving). The reality is that, thermodynamically speaking, these processes would occur naturally given enough time.
But how much time? Without the heat of the oil, you would never notice the change. If you’ve ever come across really old sugar, you’ll notice that it’s probably clumping (thanks to the fact that it’s hygroscopic and absorbing moisture causing the crystals to “dissolve” into each other), but otherwise, it’s exactly the same. It tastes the same, cooks the same, and acts the same in every way. Thermodynamics tells us what chemical reactions will occur, but not how quickly.
The speed of chemical reactions is based on kinetics. Thermodynamically, diamonds turn into graphite, but it happens so slowly that we’ll never notice it. Kinetics keeps the process from occurring at an appreciable rate.
Most chemical reactions speed up with increased heat (this is the Arrhenius equation). So, deep frying sugar, the pyrolysis reaction is accelerated. A basic rule of thumb is that a chemical reaction rate roughly doubles with every ten degrees Celsius. Between room temperature (less than 20 degrees Celsius) and fry oil (roughly 180 degrees Celsius). This is about a 160 degree temperature difference, so figure the caramelization reaction will be sped up by a factor of roughly fifteen times.
But the process of melting also takes time. So, by frying very quickly (quick enough to raise the temperature of the coating to the point of caramelization), the amount of heat needed to melt the ice cream would not get into it to allow for the melting.
Don’t get me wrong. I love the no-bake cheesecake. It’ll never replace the real thing, which I also love. Fried ice-cream is no different. I love the cheat fried ice cream, and I love the real thing. I’m not making a stand of how one is better than the other, but I think it’s a fascinating example of thermodynamics versus kinetics.