|Lemon juice||3⁄4 Cup (12 tbs)|
Cut unpeeled grapefruit and lemon into paper-thin slices then cut slices into quarters.
Discard any seeds.
Measure cut-up fruit and put into large kettle.
Add 4 times as much water as fruit. (I usually have about 6 cups of fruit so 1 add 24 cups water.)
Set kettle over high heat and bring to a full boil.
Boil hard, uncovered, for about an hour or until liquid is reduced in half.
Remove from heat and divide into three equal amounts. (Since 1 boil my mixture down to 12 cups, 1 have three 4-cup amounts now.)
Put 1 of these amounts in a kettle and add 3/4 cup sugar for each cup of fruit (this will be 3 cups for a 4-cup amount of fruit and water).
Add 1/4 cup of the lemon juice.
Set over high heat and stir until sugar is dissolved.
Bring to a boil and boil hard until mixture gives the jelly test.
Remove from heat, skim and ladle while very hot into sterilized jars.
Top with a thin coating of paraffin while hot.
Repeat these steps with each of the remaining amounts of fruit and water mixture.
Cool and store in a cool, dark place. (Makes about twelve 6-oz. jars.)
Note: To tell when the marmalade is ready to jelly, let it drop from the side of a spoon.
The drops will be thick and slow-moving when it is cooked enough.
The final test 1 make is to put a few drops on an ice-cold plate and then lift it up with a spoon and let it drop to see if it is very thick.
If you use a pan with a wide bottom, the cooking time will only be 12 to 15 minutes.
If the marmalade is cooked in a deep pan with a smaller bottom, it may take 15 to 20 minutes.