Pastry cream is a base for both Italian and international pâtisserie; it has a wide variety of uses in fresh, frozen and baked desserts, cakes and pies. A good knowledge of its basic ingredients and special attention are required to make it good and well.
In this post I will explain the pro tips and baker’s maths of pastry cream.
I will begin my analysis discussing its prevalent ingredient: milk
On the market you can find different types of milk:
- whole fresh milk (pasteurized)
- fresh semi-skimmed milk (pasteurized)
- full-fat long-life milk (UHT)
- semi-skimmed long-life milk (UHT)
- powdered milk
- condensed milk
The quality of the milk undoubtedly affects the taste of this cream; results are great when you use an excellent pasteurized fresh milk. If you use a fatter milk, however, the pastry cream can be kept longer and it will last a few days without weeping moisture (the water formation is called syneresis).
To solve this problem some fresh cream 35% (Fat content) can be added, but it must not exceed 25%. If fresh cream alone is used the pastry cream becomes glossy and thawed, rather like a fondue.
Eggs coagulate completely at 70°C but the addition of other critical ingredients such as sugar, milk and starch allows us to heat all above 80°C.
75% of recipes call for egg yolks alone because they consist of water, proteins and fat emulsion.
The natural emulsifying agent called lecithin that is contained in yolks is an extremely important element in the preparation of creams because it prevents the separation of liquids and it makes the cream bright and polished.
The amount of yolks varies depending on the recipe you are following:
The ratio for a decent pastry cream cannot be less that 200/250g egg yolk to a litre of milk, but to make a very delicate and thin cream the amount of egg yolk per litre can be increased up to 400/500g.
When the egg yolk amount is increased we must rebalance the amount of starch, too: when over 250g of egg yolk per litre of milk are used the amount of starch must be decreased by a ratio of 8g/100g added yolk.
When making pastry cream for baked preparations whole eggs can be used.
The most common type of sugar is sucrose (granulated sugar), but other types of sugar, like honey, can be used. In this case we must remember that common sugar does not affect taste, while honey does bring about particular aromatic notes that are not always harmonious with the classic flavouring pastes.
The average sugar amount for pastry cream is 300g/litre:
In baker’s maths, to make a balanced pastry cream, when the amount of egg yolk is increased we must increase the amount of sugar as well.
Using some glucose syrupe can help reducing moisture weeping (syneresis).
Flour and Starches
Cream pastry was once made with flour alone, but this thickening agent is not the best choice for a great cream.
Flour must reach 92°C to perform its thickening properties but at this temperature eggs tend to release an unpleasant sulphur smell hence flour is used in recipes that require very small amounts of egg yolk.
When flour is used in a cream its taste and structure are not as light as in creams made with starch.
On the other hand, starches do not require very high temperatures, as they thicken/gel at lower temperatures:
rice starch: 78°C
As it thickens at a lower temperature rice starch brings about more creaminess and produces the least egg smell;
cornstarch tends to gel the cream more, which can be useful when thicker creams are required.
I do not recommend potato starch because it makes the cream gluey (but it is okay in baked cream recipes).
The starch to milk ratio to make a balanced and not excessively thick pastry cream is 70-80g starch/litre of mik.
The classic flavours of pastry cream are vanilla and lemon zest.
If using vanilla bean pods, split the bean and scrape the vanilla seeds out of the beans; the pod can also be infused in milk.
The best kinds of vanilla are:
- Madagascar vanilla
- Thaitian vanilla
- Mexican vanilla
The differences among these types of vanilla are given by slightly different nuances and aromatic notes.
I recommend using organic lemons: use only the yellow zest as it is rich in essential oils. You can either add it whole and remove it later or add it finely grated to the mixture.
Have a nice and creamy dessert!