Clerical cispontine readers who receive copies of the catalogues of church suppliers should not discard unread the offering from DM Hays. It contains a hilarious paragraph clearly dictated at the point of a gun by the lawyers of "the market leaders", Hayes and Finch. DMH had compared the prices they charge for the substance called British Wine, which is not reckoned to be valid matter for the Holy Eucharist, with H&F's prices for canon-compliant 'real' altar wine. The latter, as I understand it, is guaranteed pure fermented fruit of the grape, in which the 15% or so alcoholic content needed to keep the wine in an opened bottle from going "off" is secured by adding alcohol itself distilled from wine, so that the entire product is truly fermented grape juice.
I have been disquieted to see bottles of 'British wine' in some quite respectable sacristies ..."British Ruby wine" and that sort of thing. Fathers: if it is called "British Wine" it SHOULD NOT BE USED AT THE ALTAR. "English Wine" is a quite different substance, made in English vineyards, and is true wine. But, to be absolutely sure that what you are using is wine without invalidating additives, ALWAYS use wine which states on the label that it is certified by church authorities to confom to the Code of Canons of 1983.
It's dearer but it's valid matter.