Alcohol from sugar?

I've met quite a few folk who've tried to make alcohol by fermenting sugary water. When it doesn't work, they've always got a reason – it gets too hot in my apartment when I'm out at work, or, the yeast's been lying around for nearly a year and probably died, or, it started fine but then stopped. Probably I didn't stir it enough. Or. . . 

One guy even argued with me, citing a chemical equation that 'proved' (to his satisfaction) that one mole (not the furry kind) of glucose can be turned into 2 moles each of ethanol and carbon dioxide, using some yeast 'as a catalyst', he said. Well, a little learning is a dangerous thing, as Pope observed.

Yeast is not a catalyst. It's a living organism. It releases enzymes that first convert sucrose into glucose then, through several intermediary stages, into ethanol, carbon dioxide and smaller quantities of many other organic compounds. To work this miracle, the yeast cells have to multiply, get to work, and finally die on the job. But, unlike sugar, yeast cells and the enzymes they produce are not composed solely of carbon, hydrogen and oxygen. They are much more complex than that. In particular, they require nitrogen and phosphorous (in the form of phosphates). These are not found in sugary water!

The commonest commercial yeast nutrient is diammonium phosphate (DAP) but before you go rushing off to your friendly neighborhood chemist, there is good news – a well balanced must made with fruit juices and fresh ingredients usually contains enough in the way of nitrogen, phosphates and trace elements to support a healthy yeast colony and yield a decent wine. Just don't expect sugary water to do the same. It won't.

Topping up – glass marbles

I've already described four options for topping up a new wine for storage and maturing. There's a rather ingenious alternative available for anyone who really doesn't want to add anything to the new wine. Glass marbles! After transferring the wine from the fermenter to the storage jar, simply drop in a few glass marbles until the surface level reaches the bottom of the neck of the jar. Of course you should sterilise the marbles first. Glass is completely inert and will not impart any off flavours to the wine. In fact the marbles will have no effect at all, except the desired one of raising the surface level. And of course, they can be used over and over again.

glass marbles – sterilise before use

Topping up for quality

 At the end of fermentation, the wine should be separated from the lees (sediment) and stored in a fresh vessel. If you are working with 5-litre bottles, typically, between sedimentation and volume loss, you will be able to transfer about 4½ litres, leaving a ½-litre air space above the wine. This is too much air and would impair the final quality if you simply sealed the bottle for storage. Fortunately, there are several options for topping up, some better than others, but the choice is yours:

1. Water. This is the simplest approach but of course it dilutes the wine, reducing alcohol by volume, acidity, tannin content, intensity of colour, flavour and aroma, and body. This sounds bad but some wines can benefit from judicious dilution.
2. Wine. Topping up new wine with wine from an earlier brew is often the best answer. Obviously, the added wine must be sound. Normally it should be of similar style to new wine, though judicious corrective blending is possible, for example, to increase acidity if the new wine is lacking in that department.
3. Spirits. White wines can be topped up with a neutral spirit like vodka. Red wines can benefit from an addition of brandy. This is an expensive option to be used in exceptional cases only. For example, a white wine at 13% with residual sweetness can be fortified to 15% to preserve the remaining sugar against further fermentation, producing a strong desert-style wine. Only consider this option for wines that are showing early signs of high quality, and be prepared for a long aging process.
4. Diluted spirits. For a table wine that is already the strength you want, e.g. 12%, you can top up with a 12% ABV vodka/water mix. This still dilutes all of the wine's characteristics just as water does, but it preserves the alcohol content.

In summary, Option 2 is usually the best option. Option 1 is cheap and cheerful, Option 4 is good for lighter wines, and Option 3 is for specialised purposes only.

You'll note there is no fruit juice option. Anything that adds sugar at the top-up stage is to be avoided as it is asking for trouble – flying corks, burst bottles, permanent hazes... Don't go there.

Making wine from rhubarb

Rhubarb is strange stuff. Technically it's a vegetable but it's usually cooked with piles of sugar and served as a fruit. Why does this work with rhubarb and not with, say, spinach or broccoli? Because, unlike most vegetables, rhubarb is high in acid. We enjoy fruits for their balance of sweet and sour, sugar and acid. Only, there's a catch. The acids in real fruits are malic, citric and tartaric. Rhubarb contains mainly oxalic acid which is poisonous. Fortunately, the highest concentration of oxalic acid in rhubarb is in the leaves. The stalks are perfectly safe to eat, raw or cooked, in normal quantities. This should come as no surprise. We've been eating the stuff for centuries. 

Ingredients for 5 litres:

• 2kg rhubarb stalks (no leaves!)
• 2 large ripe bananas
• 1 litre supermarket apple juice (no preservatives!)
• 800 grams granulated sugar
• Cold water, to 5 litres total

Method:

Prepare a yeast starter using a small quantity of chopped rhubarb, some apple juice and some dried wine yeast. Leave it overnight.

Chop the rhubarb into wee bits.

Chop the bananas into slices without peeling them.

Put all the fruit, juice and half the sugar into the fermenting bin

Add water enough to cover/float the fruit.

Add the yeast starter and ferment on the pulp for three days

Strain into a 5-litre fermenting vessel

Add the rest of the sugar in water

Ferment to dryness, etc. . .

Note:

Because of the bananas, this wine will froth up impressively. Don't be in a hurry to fill the fermenting jar before it has calmed down. Why add bananas? To achieve better balance. Rhubarb is high acid low sugar, bananas are high sugar low acid. They also add body. Rhubarb alone would be 'thin'.

Beer, Wine or Cider?

Let's suppose you are a complete beginner. You've decided you would like to make your own plonk but you're not sure where to start. Well, there are several good reasons for starting off by making a batch of cider. Here's a table that illustrates the main points:

	Beer	Wine	Cider
Skill level	quite high	moderate	almost none
Processes	several	several	very few
Success?	quite high	high	guaranteed
Equipment	necessary	advisable	none
Time	1 week	4 weeks	1 week

Of course, it's an oversimplification, and I'm comparing entry level methods using the easiest ingredients and processes. At a higher level, using fresh ingredients instead of commercial juices, the skill level and equipment demands must increase. But by that time, you'll have a few successes behind you and will have acquired the confidence to take on new challenges.

Beer is the most difficult because it requires boiling. Wine is easier but still needs sugar addition so that it can't be made in its original container. Cider only requires you to open the flagon of apple juice and add a little yeast - not difficult! But even if your heart is set on making wine, it makes sense to make some cider first so you'll have something to drink while you're waiting for the wine to finish.

Paraglider's Simple Cider

Volume Loss

 "I've got a bone to pick with you!", she said. 

This sounded ominous but I waited for the details. It turned out that my friend had followed my simple wine method to the letter.

"I used four 1-litre cartons of juice and the sugar syrup addition was made up to exactly a litre too. The fermentation went fine, but when I went to bottle it I only got four full litres and one about three quarters full. I thought I was making five litres of wine. Where did the rest go?"

OK. This is normal. To a first approximation, unfermented wine is just sugar dissolved in water. There's a popular misconception that when you dissolve sugar in water the volume doesn't increase. The truth is that the volume does increase, but not by as much as the volume of added sugar. The sugar molecules occupy the spaces between the water molecules. It's a neat exercise in packing but it's not perfect and the total volume does increase.

Fermentation breaks down the dissolved sugar producing CO₂ and ethanol. Some CO₂ stays in solution but most escapes as bubbles. This reduces the total liquid volume, but the effect is masked while the bubbles are present, because they take up some space, so the surface level stays artificially high. This is why volume loss appears to happen quickly, towards the end of fermentation when the bubbling stops. 

Another cause of volume loss is yeast growth. The initial yeast addition is less than a teaspoonful. But the final sediment is many times greater and largely comprises dead yeast cells. Where do they come from? Well, they are organisms and so are made of carbon, hydrogen, oxygen (which come from the sugar) and also nitrogen from the fruit juice. It follows that if you remove dissolved molecules into a sediment, the volume must decrease. Again, this is masked, because the sediment also takes up space.

All of which explains that volume loss is to be expected. Now, what to do about it? Rather than top up to get that fifth litre, I prefer to capture four full litres and one 75cl bottle either for immediate drinking or, if a bit cloudy, for cooking. Waste not, want not

Racking wine for stability and quality

Most ex-pat plonk is drunk young, often within a week of it falling clear at the end of fermentation. Some even before that, when it is still bubbling and full of suspended yeast. Extremely young wine doesn't do you any harm, by the way. In some parts of Poland, cloudy fermenting wine is even served on tap, in the bars. I tried it when last there, and wasn't especially impressed. The yeasty taste was almost acceptable but the visual resemblance to calamine lotion was a definite turn-off. No. Received wisdom correctly says that finished wine should be matured for a time before drinking. But even if you don't have time to mature your wine properly, at the very least you should separate it from its sediment at the end of fermentation. This process is called racking.

Most books on winemaking advocate siphoning the wine from the fermenting vessel into the storage vessel. This is best practice if the fermenter is bigger than 10 litres and heavy to lift. (Though better still is to ferment in a plastic barrel with a fitted tap). But if the fermenter is 10 litres or less, simply pouring it carefully into the new vessel has several advantages:

• It is much quicker, reducing the risk of oxidation
• The pouring action helps release dissolved CO₂
• Dissolved CO₂ can form bubbles in a siphon tube and stop the flow
• There is less equipment to sterilise and to wash up
• Performed carefully, the waste is no more than with a siphon.

After racking, always top up the storage vessel before sealing it. Use wine from a previous batch if you have some available (and if it is sound). Alternatively, use cool boiled water, though this obviously dilutes the wine reducing its ABV. Don't use fruit juice as this can restart fermentation, preventing clearing and pressurising the bottle.

Blending wines for balance and quality

Last year, I made close to 50 litres of red wine in two batches using my semi-pulp method. The first batch was made with black cherries and the second with brambles (blackberries). It would have been nice to use a blend of fruits in the fermentation but not possible because cherries are a summer fruit and brambles come ripe in autumn. By Christmas time, both wines were coming along nicely. Both were 14% ABV, dry and clear. Both still young and fruity of course, especially the bramble.  

Now, here's the interesting thing- the cherry tasted and smelt like cherries and the bramble like brambles. Who'd have thunk it!? In each case, the fresh fruit completely dominated the supermarket grape juice, as you might expect. Also, the bramble was brasher, with more acid and tannin than the cherry. More than was good for it, if I'm honest. The obvious solution was to blend the wines together for further maturing. After a few experiments, I settled on a 60:40 cherry to bramble mix which is now sealed for maturing in several 5-litre bottles. 

Next Christmas, I'll offer it around in the hope that someone says- I'm getting hints of Black Forest gateau and maybe some fruits of the forest too. And steel, of course. Never forget the steel.