Wash the pears very well because the skins stay on. Core them and slice thinly, about 3 to 4mm thick. Set aside about 400g pear slices for the final pitcher. Roughly chop the remaining 1kg pears for the base. Use pears that are ripe enough to smell sweet, but still firm enough to slice cleanly. Overripe pears cloud the drink and break down too fast. Choosing pears at exactly this ripeness window — sweet-smelling but still firm — protects the finished drink from two directions at once: underripe fruit wouldn't carry enough natural sweetness, while overripe fruit breaks down too quickly and clouds the water well before the infusion is complete.

Scrub the ginger well and slice it very thinly into coins. Keep the peel on. Thin slices give a clean, gradual ginger infusion. Grated ginger would make the drink cloudy and too sharp. Slicing this thin gives the ginger considerably more exposed surface area relative to its total mass — that greater surface area is exactly what lets it release flavour steadily and predictably over many hours, rather than sitting largely inert like a thick chunk would, or overwhelming the drink immediately the way grated ginger's much larger total exposed surface would.

Add the chopped pears, ginger slices, sugar or honey, lemon juice, and pinch of salt to a large pitcher or container. Pour over 3.6 liters cold filtered water and stir well. Press the pears lightly with a spoon just enough to help them release flavor, but do not mash them into pulp. That light press ruptures just enough of the pear's own cell structure to help its flavour begin releasing into the surrounding water, without breaking it down so far that the drink turns cloudy with fine fruit particles.

Cover and refrigerate for 4 to 8 hours. Taste after 4 hours. If the ginger is already strong enough, strain the base earlier. If you want a slightly warmer ginger note, continue infusing closer to 8 hours. The ginger controls the edge of the drink. Longer infusion means more spice, not necessarily more pear flavor. That specific distinction — longer infusion primarily builds ginger intensity rather than pear character — is exactly why tasting at 4 hours matters directly, since it lets the ginger's own developing strength be judged and stopped at precisely the point that suits personal preference.

Strain the infused drink through a fine-mesh sieve into a clean pitcher. Press the pears lightly, but do not force pulp through. Discard the spent fruit and ginger. Pressing only lightly here, consistent with the gentle handling throughout the recipe, keeps the finished drink genuinely clean rather than grainy or cloudy with forced-through pear pulp.

Add the reserved thin pear slices and a few fresh ginger slices to the strained drink. Add ice just before serving. Taste and adjust: more cold water if too strong; a little more lemon juice if flat; a little more sugar or honey if the pears were not sweet enough. Final volume should be about 4 liters. This final tasting checkpoint matters directly given how much both pear sweetness and ginger's developed strength can vary — building in that adjustment stage accounts for that natural variability rather than assuming a fixed recipe always lands at the same balance.