Soft serve usually contains less milk fat (3 to 6 percent) than ice cream (10 to 18 percent) and is made at about -4°C (25°F) compared to ice cream stored at 15°C (5°F). The soft serve contains air that enters during freezing.
The air content, called an excess, can vary between 0 and 60 percent of the total volume of the final product. The amount of air changes the taste of the final product. You can also buy the best soft serve mix in Australia through various websites.
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Low air products have a heavy, cool taste and look more yellow. Ice cream with a higher proportion of air is softer, smoother, lighter, and looks whiter. The optimal amount of air is determined by other ingredients and individual tastes.
It is generally accepted that the ideal air content should be between 33 and 45 percent by volume. If more, the product loses flavor, tends to shrink when it loses air, and melts faster than with less air. Below 33 to 45 percent, the product doesn't melt quickly, but it doesn't taste good.
Some forms of soft serve, like several other processed foods, contain palm oil. All ice cream should be frozen immediately to evade crystal growth. With soft service, this is achieved with special devices at the point of sale.
The pre-mixed product (see definition below) is placed in the engine storage room stored at 3°C (37°F). When the product is pulled from the outlet valve, either by gravity or by a pump, the fresh mixture combined with the target air volume is introduced into the freezer chamber. It is then stirred and quickly frozen and stored as needed.