The Science Behind Great Homemade Ice Cream
WHY YOU SHOULD CARE
What, we didn’t have you at “ice cream”? Well, here’s another shot: Ben & Jerry.
By Anne Miller
There are few tastes more associated with summer than frosty cold, creamy sweet ice cream. But at $4 a cone (not even including toppings), it’s not exactly a cheap treat for an entire family. Plus, you could whip up a batch at home in less time than it takes to find where the dog/toddler/spouse hid your keys.
So that ice-cream maker you bought in a fit of domesticity or your Aunt Mable picked off the wedding registry? Dig that baby out. Because with just four ingredients — cream, sugar, skim milk and dry or evaporated milk (all of them available at any well-stocked convenience store or even, probably, your fridge already) — a sweet treat isn’t far away.
And if you’ve tried and failed at your own iced madness, well, we’ve got the scientist who can explain what went wrong.
Professor Bob Roberts, head of Food Science at Penn State University’s College of Agriculture, makes a living as an ice cream educator. He works for the program that taught Ben & Jerry (yes, that Ben & Jerry) the biz.
Roberts offers the following tips:
Tip 1: Nail the formula, and you’ve nailed the dish.
Ice cream is a formula, based on a ratio of fat, non-fat solids, liquid and sugar. Too much fat gives ice cream a “greasy mouthfeel.” In other words, no silky, creamy smoothness here. Too much water (which comes from the milk) leads to crunchy ice crystals. Cream contributes the fat, and skim milk contains non-fat solids plus other good-for-you minerals like magnesium, potassium and calcium. (See? Ice cream is good for you! OZY and Roberts say so!)
Tip 2: You can’t make it like the pros. Don’t even try.
“Homogenization breaks up fat molecules,” Roberts says, referring to the process of using high pressure to bust up the fats in dairy. Non-homogenized ice cream “can form very, very large fat globules, and if you do that you get flecks of butter in your ice cream.”There’s just too much equipment needed. The big guns homogenize and freeze fast — faster than your Sears Kenmore can handle.
And the fast freezing keeps the water molecules in the ice cream from coming together and creating unwanted crunch.
Fun fact: By law, food labeled “ice cream” (not including anything marked low-fat, reduced-fat or “frozen dessert”) must contain at least 10 percent fat.
So here’s a secret. If you are determined to keep that treat for more than a few hours, there’s one trick a home cook can try: Add a bonus ingredient as a stabilizer. You want to make sure the water molecules stay tiny and don’t form larger crystals during the freezing process. Stabilizing ingredients can help do that. Just be warned: too much and your ice cream will have so much stick-to-itiveness it could get gummy.
Or take a tip from David Lebovitz, chef and author of The Perfect Scoop. He recommends adding a dose of alcohol to keep homemade ice cream smooth, creamy and crystal-free. Alcohol freezes at a much lower temperature than water so it keeps it from crystallizing.
Just a smidgen of booze and you’ve got real rum raisin ice cream the next time your friends come over for dessert. If you like a heavier pour, try making Purple Cows.
It’s your scoop, after all.
Tip 4: Eat the ice cream. Right now. Every last bit.
I mean, c’mon, what more do you need to know, really?
Basically, there’s a lot of industrial processing with very expensive equipment that gives ice cream a freezer shelf life. All that machinery isn’t going in a home kitchen anytime soon. So if you’re thinking of making ahead for next week, don’t bother. But if you want a dessert for tonight’s cookout that will make the neighbors “ooh” and “ahh,” have at it.
In fact, we’re so supportive, we’ll even offer our spoons up as sample testers for your next batch. Just so you can rest assured that your guests get nothing but the best. A cheesy attempt at getting us some free ice cream? Why no, we’d never do such a thing.