Custard, the queen of Italian pastry making, is now widespread throughout the world. From north to south we can find very different creams, in the north richer and fatter, softer, in the south leaner creams, with lower quantities of egg yolks and greater quantities of starches to promote stability... although at home many still use flour to thicken the cream, in reality in the professional field it is now replaced by starches, one of the most common being corn starch (structure) and rice starch (creaminess), the right balance between the two starches guarantees a perfect consistency. The choice of starches can be translated for several reasons, the first is that the flour contains amylase enzymes, these trigger, once the cream is cold, a reaction which partially breaks the gel created, letting the free water escape, after a few days the cream will be disintegrated and with a film of water on the surface, a process called syneresis. Starches, on the other hand, not having these enzymes, greatly limit this process and the cream remains stable for several days.. the other reason is that the flour or rather the starch in the flour must reach very high temperatures (prolonged boiling) to thicken, irremediably denaturing the proteins of the yolk which will release sulfur dioxide, the typical smell of rotten eggs.. the starch instead thickens at much lower temperatures (from 68 to 86 degrees) guarantees that the yolk proteins do not go beyond their limit. Sugar is very important, without sugar the custard would not exist, in fact the sugar increases the coagulation temperature of the eggs (which would already cook at 65 degrees) up to boiling temperatures, the sugar gives silkiness, absorbs and binds free water, gives softness, limits mold, slows down the bacterial action keeping the product longer and finally.... sweetens .. when we have a large quantity of yolk, the recipe must be balanced with a high quantity of sugar to prevent them from cooking but with less starch because the eggs have a thickening power .. when there is little yolk we must add more starches and we can limit the sugars .. together with the milk you can also use a certain quantity of cream which personally I would not use more than 20% for example 800% milk and 200% cream, this is because a high quantities of fats derived from milk, together with lactose, when cooling at very low temperatures can crystallise, creating a ragged effect of white dots (lactose crystallisation) and sandiness.. therefore too much cream is often added thinking of giving a certain creaminess which instead would be advisable to give with the right balance of egg yolks and starches.. type cream (medium)
Vanilla / lemon 🍋