Pasteurization of the mixture
By "pasteurization" s "we mean the heat treatment to which the mixture is subjected to ensure the perfect wholesomeness and shelf life of the finished product (ice cream, in this case).
During the pasteurization process, the mixture is subjected to temperatures that are so high but in any case lower than the boiling point. At 100 ° C, in fact, the components of the mixture would risk altering and the organoleptic qualities of the ice cream could be affected.
Pasteurization can be performed in three ways:
- Elevation of the mixture temperature to 65 ° C and maintenance for 30 minutes (low pasteurization)
- Heating the mixture at 72 ° C for 15 minutes (medium pasteurization)
- Raising the temperature to 85 ° C and holding for 2-3 minutes (high pasteurization)
Whatever pasteurization method is chosen, it is important to reduce abruptly the final temperature of the mixture at 4-5 ° C. The sudden reduction in temperature is important to prevent heat-resistant bacteria from resuming their activity. We remember, in fact, that some microorganisms capable of resisting pasteurization temperatures are able to resume their activity if the conditions were favorable. : the sudden decrease in temperature paralyzes the activity and development of any bacteria.
In addition to ensuring microbial reclamation, pasteurization is essential to favor the dissolution of sugars, partially denature proteins (albumin and globulin), help improve water retention capacity and facilitate the activity of emulsifiers and fatty substances ( made liquid by heat).
During pasteurization, the mixture must also undergo a homogenization process: in other words, the components must be perfectly emulsified by crushing the fat globules. By doing so, the fats - now reduced to very small particles - will be able to remain more easily in suspension in the liquid in which they were dispersed.
In the industrial field, an instrument called a homogenizer or emulsifier is used; at home level, it is sufficient to have a simple manual whisk or an immersion mixer.
Maturation of the mixture
It is a very important stage for the development of the ice cream. After pasteurization and homogenization, the mixture should be left to rest (or rather "mature") for 6-12 hours at low temperatures (4-5 ° C).
The maturation of the mixture allows the solid substances contained in it to hydrate perfectly and the stabilizers to complete their action. At the end of the 6-12 hours, the mixture will have reached a perfect balance and the mass will appear more dense, creamy and homogeneous.
Furthermore, the maturation of the mixture is important to reduce the formation of ice crystals in the subsequent freezing phase of the mass.
Creaming of ice cream (freezing or freezing)
During the creaming phase the mixture turns into ice cream and incorporates air: the mass, therefore, comes to life and takes on the appearance of a dense, compact and pasty cream. Whipping, freezing and freezing are three terms that, in ice cream parlors, are used synonymously and indicate precisely that process leads to the formation of ice cream.
The machine capable of transforming the mixture into ice cream is indicated by the term "batch freezer". At home level, the batch freezer takes on a simpler connotation and is called "ice cream maker".
The freezing time depends on the type of batch freezer that is used and on the ingredients of the mixture. Clearly, the higher the amount of sugar and fat in the mixture, the longer it will take the batch freezer to firm up the mass.
At home level ...
The artisan batch freezer is nothing more than a professional ice cream maker.
However, there are other types of ice cream makers accessible to all lovers of homemade ice cream:
- Accumulation ice cream maker: it consists of a refrigerating tank and a motor. Before use, the tub must be placed in the freezer for 12-24 hours.
- Self-refrigerating ice cream maker: it does not foresee the pre-freezing of the tank because it is equipped with its own refrigerating system. These types of ice cream makers are much more expensive than the previous ones.
Pistachio ice cream
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Firming of the ice cream
At an artisanal and industrial level, the firming of the ice cream is an important step that allows the mass to compact and harden at the right point.
In fact, when leaving the batch freezer, the temperature of the ice cream oscillates between -5 ° C and -8 ° C. At these temperatures it is not possible to preserve the ice cream for a long time since the mass would tend to quickly lose the structure formed during the phase. For this reason, the ice cream should be left to consolidate at temperatures of -20 / -22 ° C for a few hours, after which it can be served.
At home level, this phase is not always respected, even if it is advisable to let the mass set in the freezer for a couple of hours, immediately after the creaming phase.
Other articles on "Ice Cream Preparation - Pasteurization, Maturation, Creaming"
- Preparation of the Gelato - Balancing the mixture
- Ice-cream
- Sugar in Ice Cream
- Fats in Ice Cream
- Artisan Ice Cream - Non-Fat Solids and Dry Residue
- Types of Ice Cream
- Making homemade ice cream
- Calories of ice cream
