The apples we use for much of our cider come from old orchards which have rarely if ever received a feed, organic or otherwise. This can result in fruit which has a very low nutrient level, such that the yeast may find it a struggle to get going. On the one occasion when we added Sodium Metabisulphite at slightly below the recommended level, there was a long, worrying wait before any yeast activity could be seen, and subsequently the yeast became stressed resulting in the (temporary) production of Hydrogen Sulphide. Whilst this unpleasant aroma is apparently fairly common in the early stages of fermentation, I can't help feeling that a combination of the low nutrient levels, with the addition of yeast supressing Sulphite, contributed to this potential problem. It could also have been the result of being a little stingy with the yeast!
This year I was also concerned that the poor Summer we've had would lead to low sugar levels in the fruit, particularly for this relatively early pressing. Many trees have had bumper crops this year, but the wet weather and lack of sunshine would surely affect the ripeness of orchard fruit. It seems however, that the little bit of good weather we did finally enjoy at the end of the Summer has turned things around just in time. The OG of this batch of cider is 1049, which is better than the fruit we pressed last year at the same time. This should give an alcohol level of around 6.5%, which we're quite happy with.
The other factor we like to check at this stage is the pH of the juice. A low pH (high acidity) can result in a cider which is too 'sharp', but the big advantage is that a high acid cider is less prone to problems during fermentation and storage. This juice has a pH of around 3.0, which is pretty low. I therefore decided to forgoe any addition of Sulphite, and pitch in a good yeast.
There are many people who also swear that the best ciders are made without the use of cultured yeasts, relying purely on 'wild' yeasts to ferment the juice. I'm sure this is true in cases where there is likely to be a good supply of these wild yeasts, such as an old cider house or barn which has seen decades of cidermaking. Unfortunately, we live in the East Midlands, an area not noted for it's cider tradition, and with this being only our third season making cider in Middleton, we choose to add yeast from a packet rather than hoping for a strong wind to blow some of this rare fungus in from the West Country.
This year we are using a specialist yeast ideal for cidermaking , Uvaferm BC, which is available from Vigo. I dosed the juice shortly after pressing, and had a nosy in the fermenter the next day not expecting to see much. What a pleasant surprise to see the tell-tale ring of activity on the surface, and within 36 hours there was a thick head of yeast, and the airlocks were bubbling merrily. Every year we learn a bit more about the magic of cidermaking, and this year our first lesson has been: Don't mess around with off-the-peg wine yeasts. This made-to-measure cider yeast is the business.
The Ciderhouse (otherwise known as The Garage) is located directly below our bedroom, which means that for the next few months we will be lulled to sleep by the steady 'glop' of CO2 escaping through airlocks. Much better than counting sheep in my experience.