Encapsulated breakers, compositions and methods of use

An encapsulated breaker comprising a breaker capable of reducing the viscosity of a fracturing fluid, said breaker enclosed within a hydrolytically degradable polymer coating wherein said encapsulated breaker does not reduce viscosity lower than 50% at 5 hours at 25.degree. C. in a Standard Breaking Test, but said encapsulated breaker does not reduce viscosity lower than 50% at 70.degree. C. at a first predetermined time selected between fifteen minutes and 12 hours, but does reduce viscosity lower than 50% at a second predetermined time period selected between fifteen minutes and 12 hours after said first predetermined time at 70.degree. C. in a Standard Breaking Test and wherein said encapsulated breaker reduces viscosity lower than 50% in a Standard Breaking Test at least 20 minutes after a comparison sample which is identical in composition except that the breaker is not encapsulated.