Dairy Queen Soft-Serve
Dairy Queen Soft-Serve comes in liquid form which is delivered in bags to the individual stores. The soft-serve is then poored into containers usually in a walk-in refridgerator with mix pumps sucking the ice cream from the containers through tubes. At the mix pumps, oxygen is added. The Dairy Queen ice cream you actually eat is about 29% oxygen (with the pumps set to 40%). 1 gallon of soft serve mix creates 1.4 gallons of ice cream. The oxygen is added to create the familiar bumpy texture of Dairy Queen soft-serve.
Each store (or at least the one I work at) has a complex system of insulated tubing which sends the ice cream to each one of the soft-serve machines. The mix is kept cold and flowing in these machines until it is dispenced to the customer.
The tubes are flooded with water each night, and the mix pumps and soft-serve machines are cleaned every 2-3 nights.