Riddling racks, freezing baths and the disgorging bench

The hand tool is the pupitre: two heavy boards hinged at the top like an A-frame, each drilled with rows of oval holes cut at an angle. A bottle pushed into a hole can be set anywhere from nearly horizontal to nearly vertical, and the oval allows it to be rotated. The operator works along the rack giving each bottle a sharp partial turn and a small increase in tilt, day after day, for anything from a few weeks upward — the twist shakes the deposit off the glass, the tilt lets it slide, and the increasing angle brings it down to the closure.

The mechanised equivalent is a gyropalette: a crate holding several hundred bottles mounted in a motorised frame that performs the same programme of rotation and tilt automatically, and does in days what a rack does in weeks. It is a large capital item that pays for itself only at volume, and the argument that hand riddling produces a different result is largely one about the tightness of the deposit rather than about the cider.

The component that changed the job most is the bidule: a small plastic cup that sits inside the crown cap during conditioning. The deposit collects in the cup rather than against the glass and the cork, so it lifts out cleanly at disgorging with far less loss and far less mess. It is the reason most producers now condition under a crown cap and fit the finished cork afterwards, rather than conditioning under cork and an agrafe.

Disgorging by freezing — the à la glace method — dips the inverted necks into a bath of liquid held well below the freezing point of the cider, so that a plug of ice forms in the neck with the deposit trapped inside it. The bath is normally a brine or a glycol solution circulated through a small chiller, in an insulated trough deep enough to take the neck and no more.

Dwell time is the whole control. Too short and the plug is thin or unfrozen, so it breaks up on opening and the deposit is released back into the cider; too long and the plug extends further down the neck, which loses more cider than necessary and, taken far enough, risks freezing enough of the contents to matter. Producers establish the dwell for their bottle, their neck and their bath by trial and then hold it.

The bath needs circulation, because a static bath forms a warm layer around each neck and freezes unevenly, and it needs cleaning, because the outside of every bottle neck goes into it and comes back out wet. A bath that has been running for a season without attention is a dirty liquid in contact with the part of the bottle that is about to be opened.

Disgorging without freezing — à la volée, opening the bottle upside down and letting the pressure expel the liquid deposit before righting it — is still done by a few producers and by many enthusiasts. It requires considerable skill, loses more cider, and does not scale, but it needs no bath at all.

The bench is an arrangement rather than a machine at small scale: a cradle or clamp to hold the inverted bottle, a crown lifter or a disgorging jaw to take the cap off, a trough to catch the ejected plug and the spray, and immediately to hand the topping-up liquid, the cork, the corking machine and the caging tool. Speed matters, because every second the bottle stands open it loses gas and takes on air, so everything is laid out to be reached without looking.

The bottle is held at an angle rather than upright while it is open. That keeps the surface of the cider small and the escaping gas moving up past it, which loses less carbonation than standing the bottle vertical. On a commercial line the same effect is achieved mechanically and the interval between disgorging and corking is a fraction of a second.

Topping up replaces what the plug took with it. The addition may be the same cider, another cider, or a prepared liqueur d’expédition carrying sugar, and that choice is what sets the final sweetness of a traditional-method product — a decision made at the very last moment, months or years after the cider was made. Some lines then jet the neck with a fine spray to raise a small foam that expels the last of the air before the cork goes in.

What follows is corking, caging and a rest. The cork needs time to take its shape in the neck before the bottle is laid down or moved, and a bottle caged and boxed straight off the bench is a bottle whose seal has not settled.

A producer unwilling to own riddling and disgorging equipment has a genuine alternative. In the transfer method the bottles are conditioned in the same way and then emptied into a pressure tank under counter-pressure, chilled, filtered to remove the yeast, dosed if a dosage is wanted, and refilled into fresh bottles with a counter-pressure filler.

The equipment traded is real: no pupitres, no gyropalette, no freezing bath and no disgorging bench, but a pressure tank, a filter that can be operated under pressure, and a counter-pressure filling line instead. It suits a producer who already owns a filling line and does not suit one who does not.

The character argument between the two methods is about lees contact and about how much the transfer and filtration take out, and it is genuinely contested. What is not in dispute is that the transfer method removes the two most labour-intensive operations in sparkling production and replaces them with capital equipment.