Rinse the berries in cool water, and toss in sugar. Allow to macerate, refrigerated, overnight.

In a large saute pan, warm the berries over medium heat, until softened.

Press the mixture through a fine mesh sieve or food mill, to remove the seeds.

Submerge the jars in a large pot of boiling water, for 10 minutes. Keep warm.

Place the puree back in the saute pan, and heat, over medium heat, until thickened.

Place the lids into simmering water to soften the seal.

Taste the jam, and adjust seasoning, if needed. When it has reached the desired consistency, spoon it into the hot jars.

Wipe the edge of each jar with a clean cloth, and place the lid on. Screw on the rings and submerge in boiling water for 10 minutes.

Remove with tongs, and allow to cool.