Late July, when the morello cherries hang so dark that the blackbirds get cheeky, is when my Christmas wine begins. That sounds like too much lead time, but it is exactly right: what you put into the demijohn now stands ruby-red in the glass on Christmas Eve. Cherry is one of the most rewarding fruit wines I know, provided you do two or three things cleanly. Let us start with the most important decision.
Why the sour cherry is superior to the sweet cherry
The question comes every summer, and my answer is always the same: take the sour one. Not out of stubbornness, but because of the chemistry in the glass.
Wine needs acid. It keeps it fresh, makes it keep, and protects it from turning. The sweet cherry is a wonderful snacking fruit, but barely gets above 5 to 6 grams of acid per litre. That makes a flat wine that microbially goes down on its knees quickly. The sour cherry, above all the morello, easily brings 15 to 20 grams per litre. That is too much at first, but too much acid I can dilute with water. Too little I have to acidify afterwards, and you taste that in the end.
On top of that comes the pectin. Sweet cherries are full of pectin, which gums up the juice and keeps the wine cloudy. Sour cherries have distinctly less of it: less trouble with fining, more juice yield. Less pectin does not mean no pectin, though — more on that shortly.
The stones: let us talk honestly about prussic acid
Now the part that many guides like to skip. In the cherry stone sits a bitter seed, and inside it is amygdalin. As long as the stone is intact, this substance stays locked in and practically nothing happens. If you break, grind, or crush the stones, amygdalin and the plant's own enzymes meet with moisture, and from that prussic acid forms. This is no old wives' tale. Prussic acid is a real poison.
The rule is therefore short and non-negotiable: never damage the stones. No stick blender, no meat grinder, no fruit mill over the whole fruit. For the start I tell you clearly: pit them. A cherry pitter costs a few euros, and an afternoon hour at the kitchen table is well invested.
Anyone who likes the fine almond note that gives good cherry brandies their character may let a small handful of whole, undamaged stones ferment along: whole, not chipped, and not for weeks. I take them back out after the first few fermentation days. If you are unsure, then out with all the stones. A safe wine tastes better than a daring one.
Setting up the mash — the July day
For around 10 litres of wine I set up about 8 to 10 kilos of pitted sour cherries. I make cherry as a mash fermentation, because otherwise the juice only reluctantly releases from the fruit. The procedure:
- Wash, sort, and pit the cherries. Out with anything rotten or green.
- Crush the fruit in a food-grade fermentation bucket with a clean hand or a potato masher, the stones are out now after all.
- Stir in the anti-gelling agent (a pectin enzyme), dosage as per the package instructions. It dissolves the pectin, releases juice, and later ensures a clear wine.
- Add a small amount of potassium metabisulphite, dosed according to the instructions, against wild yeasts and acetic bacteria. Enzyme and sulphur may work overnight.
- The next day, adjust the acidity with water and the must weight with sugar (more on that shortly).
- Prepare the pure-culture yeast according to the instructions, add yeast nutrient, and add everything to the mash.
- Let it start fermenting on the mash for four to six days, at 18 to 22 degrees. Push the rising cap of pomace under two or three times a day, that draws out colour and aroma.
- Press or strain through a cloth, put the juice into the demijohn, airlock with water on top.
Measuring and adjusting acidity
Here you do not guess, here you measure. For a rounded fruit wine you want to end up with about 7 to 9 grams of acid per litre in the glass. Measure the total acidity of your mash, with a titration set or, at a pinch, with test strips. If you are at 16 grams, roughly as much water as juice brings you into the target range. But the water also dilutes sugar and body, so re-set the must weight afterwards.
With the must hydrometer or the refractometer I aim for around 85 degrees Oechsle, which later gives about 11 percent alcohol. I add sugar in small portions and measure again after each addition. And because the sour cherry brings so much acid by nature: for acidifying you expressly need nothing here. Leave lactic acid and the like in the cupboard, you need that with other, low-acid fruits, not with this one.
The right yeast and the fermentation
Cherry is a dark, powerful fruit with plenty of acid, and a robust red-wine yeast suits it. I take a Bordeaux pure-culture yeast, because it shrugs off the high acid and works out the dark fruit nicely. Always with yeast nutrient: fruit must is nutrient-poor by itself, and a hungry yeast pays that back with a stuck fermentation or with a sulphury off-note, that nasty smell of rotten eggs.
The main fermentation takes two to three weeks at 18 to 22 degrees. The airlock has to bubble and always hold water. And here I am strict, from experience: in 1998 I did not seal a demijohn cleanly, and the whole batch spoiled from vinegar taint. Acetic bacteria love air and sweetness. Keep the air out, work cleanly, touch nothing with unwashed hands.
The timetable from July to December
- July: harvest, pit, set up the mash, start fermenting, press.
- July/August: main fermentation in the demijohn, two to three weeks.
- August: first racking, as soon as the vigorous fermentation eases off. Draw the wine off the yeast sediment into a clean vessel.
- September to November: resting phase, two to three further rackings a few weeks apart. The wine clears by itself.
- November: fine or filter if needed, adjust residual sweetness, bottle.
- December: the wine sits in the bottle and settles, right in time for Christmas.
Residual sweetness, bottling, and an honest word on maturity
A cherry wine at Christmas usually likes to be a little sweet. If you sweeten a fully fermented, dry wine afterwards, you have to stabilise it first, with potassium sorbate and a little sulphur, otherwise the remaining yeast eats the new sugar and your wine keeps fermenting in the bottle. Years ago I corked a freshly sweetened batch too early, and the demijohn blew apart in the cellar at night, glass splinters up to the ceiling. Ever since the rule holds: first stabilise, then sweeten, then bottle, and be sure beforehand that nothing is still fermenting.
And be honest with yourself: from July to December is only about five months. This is no old, matured wine, but a young, fruity one, and that is exactly its charm for the festive season. If you like, set a few bottles aside; after another half year it becomes rounder.
Two honest tips to close. For the pectin I use the Arauner Kitzinger anti-gelling agent, because it is a clean enzyme preparation and because it is among the last original products of the Kitzinger company founded in 1897 by the pharmacist Paul Arauner, which closed in May 2024. This remaining stock we carry onward from Aachen. As the yeast I set up the Kitzinger Joenos Bordeaux wine yeast, for the reason mentioned above. Without enzyme and without reliable yeast, the cherry turns stubborn.
From the cellar, Magnus