Wash pears (this can be done in a clean sink full of water).
Add 1 cup water to a large stockpot and turn on high heat.
Quarter and core pears, placing them in the stockpot as you go.
Adjust heat to simmer and cook the pears until soft, stirring periodically, about 15 minutes.
In batches puree the cooked pears and their juice in a high-powered blender until smooth.
Chill the pear sauce.
Put the pear sauce in freezer-safe containers.
Label and freeze for up to a year.
Return the pureed pear sauce to the stockpot and keep warm.
Prepare the water bath canner (filled with water and jars and get the jars hot).
Ladle the hot pear sauce into hot jars, leaving 1/2" headspace.
Wipe the rims of jars and place the lids and bands on.
Can in hot water bath for 30 minutes (quarts) or 25 minutes (pints).
Remove the canner lid and let the jars sit for 5 minutes.
Remove jars from the canner and place on a towel to cool, untouched for 8 hours.