If a recipe calls for a pouch of liquid pectin, you can substitute for dry pectin. The average dry pectin comes in a box of 1.75 ounces per packet. This is the same amount as one pouch of liquid pectin. If you have bulk pectin, then one packet is slightly less than 1/2 cup by volume. So you can use a little less than 1/2 cup to equal a pouch of liquid pectin.