Canning Grapes - Whole Quantity: An average of 14 pounds is needed per canner load of 7 quarts; an average of 9 pounds is needed per canner load of 9 pints. A lug weighs 26 pounds and yields 12 to 14 quarts of whole grapes--an average of 2 pounds per quart. Quality: Choose unripe, tight-skinned, preferably green seedless grapes harvested 2 weeks before they reach optimum eating quality. Procedure: Stem, wash, and drain grapes. Prepare very light, or light syrup. Hot pack -- Blanch grapes in boiling water for 30 seconds. Drain, and proceed as for raw pack. Raw pack -- Fill jars with grapes and hot syrup, leaving 1-inch headspace. Adjust lids and process according to the recommendations in Table 1. Table 1. Recommended process time for Grapes, whole in a boiling-water canner. Process Time at Altitudes of Style of Pack Jar Size 0 - 1,000 ft 1,001 - 3,000 ft 3,001 - 6,000 ft Above 6,000 ft Hot Pint or Quarts 10 min 15 15 20 Raw Pints Quarts 15 20 20 25 20 30 25 35