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Cork Variability


Emily Robinson — San Jose, California asks,

I hope it’s OK if I take a question a bit out of the home winemaking realm, but maybe your readers will find this of interest. We use a hand-corker to cork our homemade wine, but when we bought a mixed case of wine for a party from our usual local wine shop and brought them home, we noticed that a couple of the bottles seemed to have the cork pushed up a few millimeters above the lip of the glass bottle. The bottles in question were two totally separate wines.

We know from our own home winemaking experience that sometimes the plunger on our hand corker can make the depth to which the cork is pushed vary a little from bottle to bottle. However, in commercial wines, does this mean anything? Is there anything wrong with the wine? Thanks for any of your wiz-dom on the topic!

You’re absolutely right, raised corks can either be a problem (if they’re too high, or too high of a percentage from bottle-to-bottle) or it could be nothing at all. The devil is in the details and finding out why. Bear with me while I break down a few possible causes and their implications of what you discovered in your mixed case: Possible causes 1. Uneven screwing-down of the plunger guides on the bottling line. This happens when the plungers (controlled by the automatic machinery on the bottling line) don’t quite push the cork in all the way. Usually a slightly raised cork is caught by the workers overseeing the bottling line, and they make adjustments during the run to get the corks to line up with the lip of the bottle (or a few millimeters below) for the remainder of the bottling run. Bottling lines consist of many pieces of machinery that must operate in synchronicity and every commercial bottling start-up is an art and science of making minute adjustments until all the parts (rinser, filler, corker, capper, labeler, packer,
Response by Alison Crowe.