Whipped cream
Friends of Erre4m, welcome to this new post. Today we are going to talk about a preparation that is used a great deal in pastry-making… WHIPPED CREAM.
Whipped cream is a liquid cream into which air has been incorporated to obtain a foamy, stable mixture. But are we really sure we know exactly what it takes to achieve this foamy, stable mixture? Let’s find out together.
Whipping cream, although it may seem simple and even trivial, can at times present considerable difficulties in incorporating air and serious problems of consistency and stability if it is not done correctly and with a proper understanding of the process. The “behaviour” of the cream depends on quite a few conditions, some of which derive directly from the operator’s technical skill.
To get started, let us say that air can be incorporated using various methods:
- By beating with hand whisks or stand mixers;
- By injecting air or pressurised gas into the cream;
- By forcibly blowing air into the cream by means of pumps;
- By blowing free air into the cream by means of pumps.
The first method is the most common one, and the one we all use at home, but also the “riskiest” to carry out. With this method, in fact, it is we who decide how much air to introduce into the cream, rather than entrusting it to a cream-whipping machine calibrated for the purpose.
To obtain a well-whipped, firm and stable cream, the cream must be very cold, 1–4 °C, the whipping must not go on too long, the action of the whisks must not be too fast, and finally the working environment must not be too warm. If these basic rules are respected, it is possible to obtain an excellent product free from destabilising effects such as, for example, the formation of fat globules (buttering), syneresis (loss of water from the whipped cream) and the collapse of the foam.
To fully understand what happens to the cream during the whipping process, it is worth focusing on a few aspects intrinsic to the operation.
Cream is made up of 60% water, 35% fat, 2.4% protein, 2.3% sugar and 0.3% minerals and vitamins.
The two structural elements of milk are the proteins and fats it contains, and the final qualities of any by-product derived from it depend on the interactions between these two fundamental elements. When skimmed milk is beaten, a full-bodied foam forms on the surface of the milk itself; whereas when the same operation is carried out on cream, no foam forms on its surface, yet you can see how the air, however slowly, is incorporated into the liquid. This process occurs partly because of the greater viscosity of cream compared with skimmed milk, but also thanks to the larger amount of fat dispersed throughout the cream in the form of tiny globules. These fat globules are already wrapped, at the moment of milking, in a thin protein membrane that separates them from the aqueous phase and protects them from clumping together.
After mechanical beating, these tiny fat globules find themselves embedded in a mass of water and air and tend to bind to the air bubbles thanks to the protein membrane that catalyses them.
At the start of the whipping process, the incorporation of air is irregular and very coarse; as the process continues, however, the air bubbles become smaller, grow in number and form a complex in which the “gaseous” part predominates.
The tiny balls of fat, in turn, form a firm mass over the surface of the air bubbles trapped in the cream, lending them a certain rigidity that is reflected in the consistency of the whipped product.
The “network” of fat globules not only fixes itself onto the air bubbles, making them stable within the cream, but also creates a kind of bridge that holds back and stabilises the aqueous phase of the cream itself.
As the cream is whipped, the result is generally an increasingly compact foam with an ever coarser structure. If you go further, however, you will notice it lose its sheen, gradually turning a yellowish colour due to the clumping of the fat globules that break away from the air bubbles.
The whipping time therefore plays a very important role in the success of the whipped cream. When whipping cream in a stand mixer fitted with a whisk, the optimum whipping time is between 3 and 5 minutes. Once the cream reaches its maximum level of whipping, the process must be stopped immediately, otherwise the whipped cream will collapse and turn buttery.
It is worth pointing out that, although whipping is done with very cold cream (and it has to be, because the proteins and fats in the cream are very sensitive to heat), during whipping air is incorporated from the surroundings and, in addition, the cream undergoes a certain amount of heating caused by the friction of the whisk. The ambient temperature is a factor not to be underestimated for the whisk to perform well. While in cold periods the ambient temperature is normally around
18–20 °C (which is certainly not ideal for the cream), in summer it can even reach 27–28 °C. In such cases of excessive overheating, a progressive melting of the fat globules can occur, with the consequent rupture of the protein membrane surrounding them and hence the clumping of the fat, or buttering.
But what exactly is the BUTTERING we have been talking about? It is nothing other than the agglomeration of the fat globules that normally make up butter, with the resulting separation and pooling of the aqueous part.
In certain situations, when the fat globules collide with one another, they form small granules that, as they merge, create lumps of butter. This process, indispensable in cheese-making, becomes unmanageable in pastry-making. As already mentioned, the clumping of the fat balls happens gradually, that is, when the cream begins to look slack and starts to turn yellow. There are basically two reasons for this reaction:
When the maximum amount of air stored in the cream is exceeded, the cream collapses. Helped along by the slow heating caused by the movement of the whisk, the fat globules begin to gather together until they form large clumps.
When the whipping takes place in an environment that is too warm. As we have said, the enemy of cream is temperature: indeed, above 15–18 °C the fat globules tend to release the water and air they contain, and above 30 °C the protein membrane tends to tear, letting out the fat inside it and making it impossible to save the product.
In hot weather, therefore, it is good practice to chill the whipping tools (bowl and whisk) in the fridge or freezer, and the cream itself too, for a few minutes.
As can be gathered from the foregoing, the amount of fat in the cream plays a very important role in the whipping process.
A stable foam cannot be obtained if the fat content is too low to form an impermeable network around the air bubbles. When, on the other hand, the percentage of fat is sufficient, it is easier to form “blocks” of fat globules that give body to the finished product.
There is therefore an optimum fat content (the well-known fat figure that we also find on the packaging) ranging from 30 to 40%, with an optimum value of 32–35%, which is that of counter cream.
To help the cream whip, caster sugar is normally used, in the optimum quantity of 10% of the weight of the cream itself; it acts as a stabiliser and sweetener. Larger or smaller amounts of sugar tend to make the whipped cream less stable and either too sweet or not sweet enough.
For the sugar to play its stabilising role, it is advisable to add it as follows: 1/3 of the amount at the start, the remaining 2/3 as the cream thickens. Splitting the sugar addition in this way makes it possible to partly stabilise the cream at the start of whipping without weighing it down, and to bind it definitively in the final stage with the larger amount of sweetener.
One of the most fascinating parts of the pastry chef’s craft (in my humble opinion) is that great achievements inevitably begin with knowing small but essential details... and so, HAPPY WHIPPING TO ALL!
Blog by Enrico Gumirato, pastry chef and trainer.
