Strawberries and Pineapple

This is a variation note rather than a standalone recipe: it sends you back to the book's Preserved Strawberries and asks you to swap two thirds of the fruit for pineapple. A few things about that substitution need spelling out.

• The proportions are by weightThe proportions are almost certainly by weight -- preserve recipes of this kind normally weigh prepared fruit -- though the line itself does not say. Weigh the pineapple after peeling and coring, and the strawberries after hulling, or the ratio drifts.
• Cook the pineapple firstThis is the hinge. Pineapple takes 15-20 minutes of simmering in the syrup to turn tender and translucent; strawberries collapse in three or four. Bring the pineapple most of the way to done, then add the berries for the final few minutes so they stay whole.
• Cut sizeThe original assumes fruit prepared as for preserves. Dice or shred the pineapple to roughly berry size so the two cook at similar rates and the finished jar looks deliberate.
• SugarMany period strawberry preserves run close to pound for pound, sugar to fruit. Follow the base recipe's ratio as given rather than cutting it.
• SetBoth fruits are low in pectin, so this thickens by evaporation rather than gelling. Cook to about 220F at sea level for a spooning consistency; expect a loose preserve with fruit suspended in syrup, not a firm jam.
• Fresh versus canned pineappleCanned crushed or diced pineapple works. Drain it well and count the juice as part of the liquid, or the batch will take much longer to reduce.
• StorageIgnore any period instruction to seal with paraffin or to invert hot jars and call it done. Either refrigerate the finished preserve and use it within a few weeks, or follow a current tested boiling-water canning procedure for jams and preserves.
• YieldTwo pounds of prepared fruit with the matching sugar gives roughly five half-pint jars, depending on how far you reduce it.