The Red Wine Reduction Maths of Gravy

hydrogen bonding

 

As a vegetarian, making gravy for a traditional roast with only veg can be tricky. Usually I’d use Ina Perlman’s gravy powder, but this week I decided to try a red wine reduction instead. I googled to find a recipe, but straight away hit a huge, insurmountable problem! The recipe called for leftover wine. So, I googled Leftover Wine, thinking it was the brand name of some special red wine reduction ingredient. Turns out it’s the wine that people don’t drink the night before. Obviously, I had to give up on my plan to make a red wine reduction right there!

red wine reductionBut then Analize explained to me that I could also use the horrible box wine that’s been in my cupboard forever. A while back someone told me that Woolies dry red box wine is the best kept secret in town, and so I decided to try it and see for myself. It’s not a secret. Nobody’s talking about it because it’s not true. That particular box wine was undrinkable. At least for me. But it would do for a reduction.

So…what is a red wine reduction anyway? It’s basically red wine that’s been heated until the volume of the liquid has been reduced by approximately half. It’s tasty because it keeps the red wine flavours without tasting overwhelmingly alcoholic.

The science behind it is interesting and a tad confusing. We know that wine contains both ethyl alcohol and water molecules. Alcohol evaporates at a lower temperature than water (78 degrees Celsius for alcohol vs 100 degrees Celsius for water), so strictly speaking, when the wine is heated, all the alcohol should evaporate long before the water starts to boil and evaporate. Because of this, we would expect that once reduced to half its volume, the wine reduction would contain no alcohol at all. But it does! The good news is that it retains up to 10% of the alcohol.

But why is this? Apparently, this happy phenomenon is due to something called hydrogen bonding, which involves weak electrostatic forces. In the world of molecular bonding this can be compared to the vague attraction you may have to a fling as opposed to the lifelong connection to your soulmate. hydrogen bondingNobody would waste a good Shiraz getting dronk verdriet over the breakup of two hydrogen bonded molecules. I’ve just finished watching season 6 of Sex and the City. Can you tell? So…these forces form weak bonds between the molecules of the two liquids in the wine, to create a uniform mixture known as an azeotropic mixture. When the mixture is heated, the hydrogen bonding ensures that some water molecules evaporate along with the alcohol, while equally ensuring that some of the alcohol molecules remain bonded to unevaporated water molecules. Remember that red wine on average contains not more than 14% alcohol to begin with, so the final reduction percentage makes sense. Does it? Or is it just that handy wine maths thing again?

The recipe is not rocket science, once you get around the leftover wine conundrum. You fry onions in olive oil or butter then add the wine, rosemary and vegetable stock. Simmer until the volume is reduced by about half. If you want less alcohol in your reduction, reduce the wine to half its volume first, before adding the vegetable stock and reducing it further.

I just love being a vegetarian!! So many reasons and ways to “drink” wine. Anyone for lunch?

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