Whipped cream has numerous uses in the kitchen, most obviously simply as a garnish for sweets such as cakes and puddings, but also to lighten other mixtures and as a topping for drinks and coffees.
It is usually made from whipping cream, which has a fat content of around 30% - 35%. Sometimes a product known as thickened cream is used, which has a similar fat content, but uses gelatine or vegetable gum as a thickening agent. If you are vegetarian, read the label carefully.
So why does cream hold its shape when whipped? When you beat cream air bubbles are introduced into the liquid, in much the same manner as beaten egg whites. As the cream is further agitated, proteins are trapped in the walls of the bubbles, providing a structure that holds the liquid cream in a semi-stable foam.
Milk has the same protein content as cream, yet you can beat milk until the cows come home (sorry) and still never achieve whipped milk. Obviously the reason lies with fat. Milk actually does form protein air pockets just like whipped cream, but they disappear just as soon as you make them. Milk only has a fat content of 4% and therefore is nowhere near as viscous as cream. The higher fat content of cream means that it flows much more slowly. In addition, the behavior of fat aids in the foam structure. The fats gather in the bubble walls where the protein structure is forming. Surface forces cause these fat globules to rupture, thus exposing soft fat molecules that adhere together readily. In essence, you and your whisk are creating a fat and protein net in which to catch air.
When whipping cream, always use chilled cream and chilled bowls. The fats in cream melt just like the fats in butter. Notice when you heat cream in a pan it suddenly becomes very liquid. This is when the fats have fully melted (32° C (90° F)). However, the fat in cream becomes soft at much lower temperatures so a stable whipped cream foam will be difficult to achieve. Temperatures below (7° C (45° F)) are recommended. Place the cream in a bowl and gently, but firmly whisk the cream. It will start to thicken after 3 or 4 minutes. Keep beating until the cream has formed soft peaks and store in the refrigerator. If the structure breaks down after some time, simply beat again for a few minutes to revitalize it.
Ever wonder how butter is made – well beat your cream too much and you will find out. Over beaten cream will form small lumps in the foam - these lumps are butter. The further you agitate the mixture, the larger the butter lumps become. Eventually you will be left with semi-solid butter and liquid buttermilk.
There are wonderful variations on simple whipped cream. Crème Chantilly - named after the chateau of Chantilly in France is a famous mixture of softly whipped cream that has icing sugar and liquid vanilla extract added towards the end. You can make your own flavoured whipped creams by adding all sorts of liquids and flavourings. Just make sure to add them after you have whipped the cream, as they may affect the creams ability to foam. Try the liquid from poached fruit, or your favourite liqueur.