Int sugar great! Candy floss, Irn Bru, Curly Wurly, its a component of all the major food groups. It is also essential for wine either as part of the fruit or as an additive. It feeds the yeast being broken down into unwanted carbon dioxide and very much wanted ethanol.
There are a number of ways of measuring sugar in a wine must – the easiest is by weight just chucking it in. This is a little cavalier as it takes no account of the fruit sugars already present. This is the main criticism of British fruit wine recipes as they add far too much making ultra sweet and hyper alcoholic wine.
Recording sugar with “brix” or “gravity” can get you a decent idea of the alcohol content once a wine has fermented rather than just using weight. Brix is a percentage of sugar to water and I feel not much use to the home wine maker. I use gravity, recording the “start gravity” and compare it to the “final gravity” with a hydrometer. This little buoy floats high when sugar content is high as the dissolved sugar is dense. As this sugar is respired into alcohol the hydrometer drops down as it is less dense than both water and the sugar dissolved in it.
The closest thing to a rule is a starting gravity of 1.09 and then letting it ferment to dryness with a gravity of 0.091 to 1.00 This creates a wine of about 13% ABV. Racking a wine is not a science so you can never be quite sure. If you want a stronger wine more sugar can be added to the recipe but it is better to gradually “feed the yeast” adding sugar incrementally. Sugar is a preservative and in too high a level it will kill the yeast or certainly slow it down potentially allowing it to spoil or oxidise.
Not every one wants to have a dry wine as sweetness is part of the holy trinity of wine tastes along with tannin and acidity. If this is the case back sweeten. This is the addition of sugar at the end of fermentation after the wine has been stabilised. Stabilising wine means that the hungry yeast will not activate again when the sugar to taste is added. If a wine is not stabilised a second fermentation will start, alcohol will rise, sediment will build up, dogs live with cats and total wine anarchy reigns.
This is sugar that is present in the fruit that mixes into the water during fermentation. Grapes have enough ambient sugar that none is needed to be added. using blackberries, quince or lego-men heads we are no so lucky and have to add it. Always take a gravity measurement when the ambient sugar is present in the must.
When making wine you do not need to be choosy about the sugar. Any white granulated sugar will do so there is no need to buy the more expensive brewing sugar. I have no idea if it is dextrose or sucrose, to me it is Tate and Lyle and it makes alcohol.
Few wine recipes use brown sugar except some fruit sherries and some beetroot recipes as far as I know. It is not that brown sugar is bad but it does impart the molasses taste after fermentation that could overpower the taste of your fruit.
Honey is used by weirdy beardy mead brewers and a few wine makers. Like brown sugar it will imprint a taste on the wine at the end of fermentation but it will be subtler and more varied. You can be a total sugar slut but you have to be more chaste with honey and select the best tasting because of this. A third extra honey by weight will be needed so1kg of sugar is equal to 1.3kg of honey. No one says you have to use only one though and the total sugar content could be divided between both sugar and honey for a subtle addition of flavour rather than a full on mead taste.
Some recipes use saccharin to back sweeten a wine at the end of fermentation. This is because yeast cannot metabolise it so it remains 100% in the wine. Personally I think this is heresy and performed by mouth breathing troglodytes… it should also be noted I never ever tried this and you should decide for yourself.