Pudding. Custard. Mousse. They all kind of look the same. They're all soft, creamy foods. So what's the dif?
The short version?
In America, at least, pudding is typically the term assigned to a milk or cream-based dessert which is thickened by starch. Usually, but not always, cornstarch.
Custard, on the other hand, is a milk or cream based dessert thickened by egg.
Mousse relies on egg, too. Primarily egg whites, which are whipped to a froth and then folded with other ingredients for an airy, unique texture.
That's the short version. But there's more to the story than that.
The long version?
The simplistic view that eggs are the only difference is fraught with inconsistency.
As Chow.com aptly puts it,
But it’s not quite as simple as saying, “If it has eggs it’s custard; if it has starch it’s pudding.”Professional Baking points out that there is an overlap: Cream puddings, it says, use a custard base but are thickened with starch. Pastry cream (the stuff you find in an éclair) is a cream pudding—a custard-pudding hybrid.
So, let me address some exceptions.
There are plenty of pudding recipes which employ eggs.
This vanilla pudding, for instance, contains egg, but it doesn't completely rely on it for thickening the mixture. It also includes cornstarch, which propels it from custard to pudding territory. Or is it a custard with starch? Tough call.
Some custard recipes include starch.
Yep. Some custard recipes include starch. Not all, but some. This great post makes some notes on the differences between how you prepare custard and pudding, and examples of custards with starch.
Mousse doesn't always include egg whites
And there are mousse recipes that don't include egg whites, but do include egg yolks. There are some recipes that don't include eggs at all, but rely on whipped cream to impart the airy-rich texture.
To summarize: there are blurred lines.
While there is a general division between pudding, custard, and mousse, recipes cross the borders all the time. Ultimately, you're not going to be denied dessert if you mis-categorize one (not by me, anyway). But I'm a big believer in the idea that you should learn the rules before you break them...so hopefully, with this post, I've given you a brief look at the rules.
Now go ahead and break them.