Place 5 clean 250 ml mason jars on a rack in a boiling water canner. Cover jars with water and heat to a simmer (180°F/82°C). Keep jars hot until ready to use. Preheating Bernardin® lids is not advised.

The sealing compound used for our home canning lids performs better at room temperature than it does pre-heated in simmering water (180°F). Simply wash lids in hot, soapy water, dry, and set aside until needed.

Preheating can lead to less vacuum being achieved during water bath canning, and to buckle failures during pressure canning. Wash and trim rhubarb; cut into 1/2 inch (1 cm) pieces. Measure 8 cups (2000 ml); set aside. Wash and remove zest from oranges and lime using a zester or grater; set aside.

Squeeze juice from oranges and lime; measure 3/4 cup (175 ml), adding water if necessary; set aside. Peel gingerroot and grate enough to measure 2 tsp (10 ml). Combine rhubarb, rind, juice, sugar and gingerroot in a large, deep stainless steel saucepan.

Stirring frequently, bring to a boil; reduce heat and boil gently until mixture thickens and reaches gel stage, about 30 to 35 minutes. Gel Stage Tests (Remove pot from heat while conducting selected gel test) : Dip cool, metal spoon into jam. Lift spoon moving it away from steam.

Gel Stage is reached when mixture sheets off spoon. Place spoonful of hot mixture on chilled plate; place plate in freezer until cooled. Gel is achieved when product does not run together when separated with spoon.

Cook mixture to 220°F (104°C) or until it reaches a temperature that is 8°F (4°C) above the boiling point of water at your elevation. Quickly ladle hot jam into a hot jar to within 1/4 inch (0.5 cm) of top of jar (headspace).

Using nonmetallic utensil, remove air bubbles and adjust headspace, if required, by adding more jam. Wipe jar rim removing any food residue. Centre hot sealing disc on clean jar rim. Screw band down until resistance is met, then increase to fingertip tight. Return filled jar to rack in canner.

Repeat for remaining jam. When canner is filled, ensure that all jars are covered by at least one inch (2.5 cm) of water. Cover canner and bring water to full rolling boil before starting to count processing time. At altitudes up to 1000 ft (305 m), process -boil filled jars - 10 minutes.

When processing time is complete, remove canner lid, wait 5 minutes, then remove jars without tilting and place them upright on a protected work surface. Cool upright, undisturbed 24 hours; DO NOT RETIGHTEN screw bands. After cooling check jar seals.

Sealed discs curve downward and do not move when pressed. Remove screw bands; wipe and dry bands and jars. Store screw bands separately or replace loosely on jars, as desired. Label and store jars in a cool, dark place. For best quality, use home canned foods within one year.

Processing: At altitudes up to 1000 ft (305 m), process -boil filled jars - 10 minutes - 10 minutes.

Altitude-adjusted processing table: At altitudes up to 1000 ft (305 m), process -boil filled jars - 10 minutes