Gooseberry Jelly

4 1/2 lbs fully ripe gooseberries, to make 5 1/2 cups gooseberry juice
1 cup water
1 (1 3/4 ounce) box pectin (Sure-Jell)
1/2 teaspoon butter or margarine
7 cups sugar, measured into separate bowl

Crush gooseberries thoroughly, one layer at a time, or grind them. Place in saucepan; add water. Bring to a boil. Reduce heat to low; cover and simmer 10 minute.
Place three layers of damp cheesecloth or a jelly bag in large bowl. Pour prepared fruit into cheesecloth. Tie cheesecloth closed; hang and let drip into bowl until dripping stops. Press gently.
Measure exactly 5-1/2 cups juice into 6- or 8-qt. saucepot.
Stire pectin into juice in saucepot. Add butter to reduce foaming.
Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly.
Stir in sugar.
Return to full rolling boil and boil exactly 1 min., stirring constantly.
Remove from heat. Skim off any foam with metal spoon.
Ladle immediately into prepared jars, filling to within 1/8 inch of tops.
Wipe jar rims and threads; cover with two-piece lids. Screw bands tightly.
Process in a boiling water bath for 5 minutes.