A Briton who has worked in almost every grapey country, Ryman has turned his attention to the grist mill at the behest of the national brewer, Whitbread; the resultant beer, Ryman's Reserve, has just been distributed to a couple of hundred pubs nationwide.
Behind Whitbread's offbeat initiative is the notion of bringing to beer some of the glamour associated with wine. But why was Ryman tempted?
Perhaps because he thought it might help him to sell wine to Whitbread's pubs and off-licences. I suspect, however, that he has now caught the beer bug.
'I used to think an international lager was a good beer,' he says. 'I had forgotten how varied and complex beer can be.
'For the wine-maker, the grape is everything. All you have to do is utilise its potential. For the brewer, there is not only the choice of grains but also the malting technique, the infusion, the hops - what an unforgettable flavour] - the yeast, a multitude of elements. How on earth can you be sure what you will get out of all these permutations? If I had been left to my own devices, I would probably have produced something undrinkable.'
Ryman was first invited to chew over a selection of malted grains, nose some of the classic hop varieties and sample fermentations from different beer yeasts. Then he tasted a selection of well regarded styles of brew, ranging from lagers and wheat beers to ales, stouts and barley wines.
He decided to work with wheat as well as the more usual barley, seasoned with the famously delicate Saaz hop (from Bohemia) or the more assertively aromatic Styrians hop (from Slovenia). He wanted the lightness and refreshment of a wheat beer but the complexity of flavours in a bitter or pale ale.
So Ryman decided to use more than one yeast, a procedure less common in Britain than in Belgium. He also proposed maturing the beer on protein and yeast sediment, which occurs naturally to a degree in cask-conditioning; he was looking for a 'real ale', though he used the wine term 'on lees'. He also suggested that the beer might have more length if it were matured on oak chips; one or two beers still have this oaky character, though they are hard to find.
About 15 experimental versions of Ryman beer were made at Whitbread's pilot brewery in Luton, before two or three were deemed worth pursuing. Ryman made two visits to Castle Eden, a village 10 miles from Durham, where the smallest of the company's five breweries was to make the beer on a commercial scale.
Whitbread, established in 1742, is something of a Jekyll and Hyde outfit. One moment it seems determined to close its traditional breweries and make under licence an undistinguished version of Heineken lager; the next it is painstakingly recording its history, rediscovering its heritage and creating splendid beers at Castle Eden.
This brewery, which began as a coaching inn in the mid-18th century, retains a facade that reminded the art historian, Sir Nikolaus Pevsner, of a stable block. It is very much the village brewery: the grandly moustached manager, Jim Kerr, employs his wife Michelle as his secretary; head brewer Tony Rowsell is helped by his daughter Lucy at the reception bar in an adjoining house called Beechwood (which, mysteriously, has its own Hammond organ). Kerr's sport is rugby, but the day I called the staff were preoccupied with supplying beer for a cricket match.
These beer-makers have doggedly co-operated with Whitbread's every whim in order to ensure the survival of a brewery in the middle of nowhere. All the staff took an interest when they were chosen to make a 'London' porter, and it left them with a thirst for speciality products.
But the news that a guest brewer was coming initially left them horror-struck, says Kerr. 'When I heard that Hugh Ryman was really a wine-maker, I asked a friend in that business about him. The friend fell to his knees. After that, I realised Hugh Ryman must be pretty good. Obviously, he knows a lot about the production of drinks in general, and his wine background brought a fresh perspective to beer.'
When it became clear that Ryman's role was to design the beer, not turn the valves, Kerr was even happier (one of a brewer's many nightmares is that an infusion becomes too thick and clogs the vessels). Ryman brought his samples from the pilot brewery. Kerr liked the 'different' character of the beers, but thought them a little light in flavour. He was impressed with Ryman's ability to 'play with ideas'.
The final version involved the brewing and blending of two beers. Three-quarters of the blend comprises a wheat beer, made with a lager yeast; the remainder is a pale ale. Both are specially brewed, though the pale ale does have some resemblance to a Whitbread beer sold in America.
The two beers are seasoned only with Bohemian Saaz hops, which are added on three occasions to increase the aroma. The hop is depicted on the label and on pump-handles in pubs.
Whitbread recently introduced a beer hopped only with the east Kent variety Goldings, and is planning another one, based on the typical Hereford and Worcester Fuggle hop. All these new beers, which have been dubbed the 'New Classics' and will be available for one month only, are aimed at what Whitbread describes as 'beer thinkers' (as opposed to beer drinkers?).
Ryman's Reserve, the beer for July, is bone-dry, crisp and lightly fruity, with just a suggestion of tangerines. No fruit is added, but that flavour could derive either from the wheat or the yeast.
There is, perhaps, a slight fruity-woody aroma like that from a box of dates at Christmas, but no obvious oak-smoke character (though a small proportion of essence of smoked oak was used). The only challenging element is its slight haze, which is typical of the most traditional of Belgian and German wheat beers.
'It's not cloudy,' says Kerr, 'it's opalescent.' A beautiful beer for a summer evening.