The power of prosecco

The 13th of August marked the most important day in the calendar year - National Prosecco Day! And in honour of this special occasion, Eva Higginbotham made the great sacrifice of spending an afternoon sampling prosecco at the Cambridge Wine Merchants with founder Hal Wilson and scientist and local wine expert Clare Bryant, to learn about the science of sparkling wine.

Eva- It is an extremely hot August day. And I am here in the Cambridge Wine Merchants, ready to celebrate national Prosecco day. And with me, I have Hal Wilson.

Hal - I'm the managing director and original founder of Cambridge Wine Merchants.

Eva - Wonderful. And I also have with me, friend of the show, Claire Bryant. Hi Claire. So we are here to talk about the science of sparkling wine and to start off with, how do we actually make regular wine in the first place?

Hal - We ferment ripened grapes with either natural or innoculated yeast. It works its magic and terms of the sugars in the juice into alcohol.

Eva - So what does fermentation actually mean? What is the biological process of fermentation?

Claire - So it's where the natural sugars are converted to alcohol with a side product of carbon dioxide. So it's literally a yeast driven reaction where the alcohol is the beneficial off-product of it. But the balance that you get within a wine will depend upon the fruit and the sugars, along with the CO2 in sparkling wine, give it its flavour.

Eva - And we're going to be trying some sparkling wines today.

Hal - Safely, but with some ceremony, always a good idea to hold the cork and the rotate bottle. [pop!]

Eva - Oh, lovely foam there. All right guys. Cheers. Very tasty. Claire, what do you think?

Claire - Delicious prosecco through and through! Absolutely light frothy, delicious, fruity. Prosecco is made with a single grape. So the flavour is always very, very distinctive.

Eva - How do you actually make fizzy wine, fizzy?

Hal - So basically after a first fermentation, you have a still wine. What we do is re-ferment that wine by the addition of more yeast and more sugar. There's very little sugar left in the wine after the first fermentation. Now you can either put that into a single bottle and that's the single bottle that you will buy and pour into your glass, which we might call, but we might get sued for it, the Champagne method, or you can put that liquid and the sugar yeast solution into a large tank. Um, both of them will be under pressure during that secondary fermentation. And the CO2 has nowhere to go except back into the liquid. Then you will finish the production by adding sugar to make it however you want your wine to end up. And put the cork in and basically bottle it and have it ready for sale.

Eva - Apart from when you drink something fizzy, you obviously have the touch sensation on your tongue of the fizzing and the bubbling up against, up in your mouth, does having the CO2 in there change anything else about the flavour?

Claire - So the CO2 can alter the flavor of the wine. It's supposed to. The bubbles and the bubbling effect through the wine is supposed to make the wine taste much better. The base wines are actually quite acidic and the bubbles are well known as enhancers of flavour.

Hal - And in fact, it's one of the great marketing triumphs of Champagne that they've made a fairly ordinary based wine into something that's quite magical.

Eva - Claire, people often say that when you drink fizzy wine, you get drunk quicker. And they also say actually that the hangover is worse. Is there any science behind either of those? Yes. So firstly, you tend to drink Champagne on an empty stomach. It means that your stomach's empty, it's ready and waiting to absorb anything you put in it. And so the wine will get absorbed across your stomach lining very quickly, but the Champagne bubbles actually have an enhanced effect to make you take up more of the alcohol into your blood. And that's because the bubbles are made of carbon dioxide. Carbon dioxide, we think, causes increased blood flow to the gut. The more blood flow you've got across your gut mucosa, the more absorption that will happen. So in fact, there was a really nice study done where they got some people to drink two glasses of Champagne, and then five minutes later they measured the blood alcohol. And so after two glasses of Champagne, your blood alcohol was about 0.54 milligrams. Okay. Now the driving limit is 0.8 milligrams. Okay. But if you do the same as still wine, the alcohol level was about 0.3 milligrams. So drinking Champagne, it's almost double the amount of alcohol uptake that you get. The bad hangover I don't know, but I must admit I do have a bad hangover if I've drunk Champagne on an empty stomach, but I think it's the empty stomach rather than anything else that's the problem.

Eva - So Hal, why do we drink Champagne, Prosecco, Cava, out of flutes? So those different shaped wine glasses. Rather than a regular wine glass, or a mug as I might in my house!

Hal - I would not recommend a mug because what you're missing out on is looking at the bubbles and the idea of a tall glass is you've got more chance to see those bubbles rise. And I think that is most of the story.

Claire - But there is a key point, your glass needs to be clean because if you've got any residual soap, then it flattens the Champagne or the sparkling wine very quickly. And the reason for that is that the soap provides a surface tension that attracts the bubbles and the bubbles then pop.

Eva - Okay, good to know. Do you have any tips for choosing a good one? Hal?

Hal - If you prefer your wine dryer, look for a brut Prosecco. Price is most people's guide. I would probably advise people not to go for the very cheapest in the shop.

Eva - I would never...

Hal - Although I quite understand it. So just go for an honest £11 bottle, and I think you'll have some quality. And in Champagne, buy the most expensive champagne you can afford. You will like it more, but there are some deals out there.

Eva - Fantastic. I'll drink to that. Thanks guys. Cheers.