In principle Cappuccino powder is used like coffee-whitener to "whiten" coffee, however, with the main purpose of getting a thick stable foam layer on the surface of the coffee after reconstitution. A lot of Cappuccino powder is sold already mixed with instant soluble coffee and sugar - ready to use.
The foaming ability is achieved when the powder releases the gasses entrained in the powder
- Occluded gas in form of air and CO2; the latter has by purpose been injected into the concentrate prior to drying
- Interstitial air, due to the agglomeration of the product.
The composition of the concentrate is slightly different from that of coffee-whitener to enhance the ability to form a thick layer of stable foam. The typical composition is as follows:
|Glucose syrup or maltodextrine with a DE of 25-30:
|Vegetable fat with melting point 35-40ºC:
|Low-Heat skim milk powder:
|Artificial cream flavour, colour and emulsifier:
During the mixing of the ingredients at 60-65ºC to a total solids content of 50-55% it is important to avoid incorporation of air into the concentrate, as it will take up "space" for CO2 - therefore the mixing should be done under vacuum. It is further important to avoid long holding times at 60-65ºC due to age-thickening.
After mixing the concentrate is homogenized in two stages at 150/50 bar g, followed by a pasteurization to 70-75ºC for 15 sec. Then it is cooled to 50-55ºC.
Injection of liquid CO2 is done using the LSI unit, see page 87, as this offers the best dissolution of the CO2 in the concentrate. The amount of liquid CO2 that can be dissolved in the concentrate depends on the temperature and pressure of the concentrate. Low temperature and high pressure results in more dissolved CO2.
Drying of the concentrate is done in a Multi-Stage Dryer with nozzles, see page 203, as this plant offers the best possibility for agglomeration to increase the content of interstitial air. Drying air temperature is typically 200-210ºC depending on ambient conditions. The bulk density of the final powder is typically 0.15 g/ccm, the foam height is approx. 10 mm, with a stability of ½-1 hour.