TEPHRA AND PYROCLASTIC ROCKS. The rapid eruption of expanding gases results in the obliteration and fragmentation of magma and rock. The greater the explosivity, the greater the amount of fragmentation. Individual eruptive fragments are called pyroclasts (fire fragments).Tephra (Greek, for ash) is a generic term for any airborne pyroclastic accumulation.Whereas tephra is unconsolidated, a pyroclastic rock is produced from the consolidation of pyroclastic accumulations into a coherent rock type.he greater the explosivity, the greater the amount of fragmentation. Individual eruptive fragments are called pyroclasts (fire fragments). Tephra (Greek, for ash) is a generic term for any airborne pyroclastic accumulation.
Test the temperature of the milk with an instant-read thermometer once the milk has begun to steam and show small bubbles. Milk is considered to be scalded once it exceeds a temperature of 180 degrees F. Select a heat-proof measuring cup that is capable of holding at least twice as much milk as you wish to heat.
In the ultra-pasteurization process, milk or cream is sent through pipes where it's heated almost instantaneously to around 280Â° and then cooled again almost as quickly. This is as compared to the regular pasteurization process which heats milk to a minimum of 162Â° for fifteen seconds. On the one hand, ultra-pasteurization means that enormous quantities of milk can be processed much more quickly than any other pasteurization (or safety regulation) process. The milk is also shelf-stable for several months. On the other hand, the treatment changes the taste and texture of the dairy.