Combine the sugar and the water in a 3.78-L/4-qt sauce pot. Cook over high heat until the sugar turns amber brown, 180°C/360°F. Meanwhile, bring the pear cider to a simmer.
When the sugar reaches the desired temperature, slowly stir in the hot pear cider using a whisk.
Turn the heat down to medium. Add the pears and cover them with a clean towel to help keep them completely submerged and thus cook them evenly. Seckel pears are usually hard, even when ripe. Therefore, poaching time may be up to 10 minutes. Always check the extra pear, which is for poking and probing to check for doneness so as to not damage those that will be used for service. The pear should be tender but not falling apart. You should be able to easily slide a paring knife into it.
Once the pears have cooked through, remove them from the liquid with a spoon and transfer them to a sheet pan and cool in the refrigerator. Once they are cool, transfer them to an airtight container and reserve refrigerated. Discard after 2 days.
Reserve the hot caramel and pear stock for service, keeping the liquid hot on medium-low heat. The pot should be covered to prevent evaporation. This liquid can be used about four or five times to poach pears, improving its flavor each time, but after a while it will become too liquid and its caramel color will dissipate.