To prepare pulp: Quarter and core pears.
Cook until soft, adding only enough water to prevent sticking.
Press through a sieve or food mill.
Add remaining ingredients; cook until thick, about 35 minutes.
As mixture thickens, stir frequently to prevent sticking.
Pour hot into hot jars, leaving 1/4-inch head space.
Process pints and quarts 10 minutes in boiling water bath.