Faults and additives FAQ

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Faults and Additives Frequently Asked Questions - as part of the Cider makers FAQ

Contents

Problem corner

"Rope", "mouse" and vinegar are just some of the possible faults which can develop in cider or perry.

slightly ropey

  • Q: Can slightly ropey cider be saved?

A: An old home-winemaking remedy was to add Campden tablets at a dose of 1 or 2 per gallon to kill the bacteria causing the rope and then to use a hand whisk to break up the 'strands' of rope. Leave the wine / cider to settle and then rack off any remaining fall-out debris. Filtering can also be used to take out any lumps / clumps / strands.

rotten eggs smell

  • Q: My cider smells of rotten eggs... Help!

A: Geoff Morris replies:
Hydrogen Sulphide (H2S) is the gas that typically smells of rotten eggs and is formed during fermentation usually as a problem with the yeast.

Wild yeasts are more likely to produce it than cultured yeast. It is caused by the yeast looking for a source of nitrogen. If usable nitrogen is in short supply it will strip the nitrogen from Cysteine, one of the amino acids found in proteins. Cysteine contains sulphur, which the yeast does not need and is released as hydrogen sulphide which wreaks of bad eggs.

It is important not to let it linger, as it could ruin your cider by reacting with the alcohol to produce mercaptans. If you think bad eggs have a rotten smell, you should try a mercaptan. Imagine a cocktail of bad eggs, rotting cabbage, and dead bodies, and you are about halfway there... You do not want this in your cider. Especially as once it has formed, it is very difficult to remove!

Solution: if your cider is still fermenting, add a little more sulphite, to kill off the wild yeasts, add some sugar, some yeast nutrient, and some champagne yeast. Ideally, use a starter bottle to get the champagne yeast vigorously fermenting, before adding it to the cider. The extra fermentation will drive off the H2S.

Cider turns green or black when opened

Q I have made some quite reasonable cider but opening to sample can result in the cider taking on a greenish tinge , or in the worst case going black. Looks a bit like oxidation. What might be happening and how to avoid?

A This is almost certainly classic iron or copper contamination, which results in catalytic oxidation of polyphenols by metal when the bottle is opened. Take a good look at your equipment and vessels and eliminate all contact with metals other than stainless steel, acid resistant bronze or (briefly) aluminium.

That will not help you now, though, but will prevent problems in the future. For now there is not much you can do except to add citric acid e.g. 0.5 grams per litre which will help to 'chelate' the iron. Addition of wheat bran was an old remedy (3 ounces fresh wheat bran per 10 gallons!) because it contains phytic acid which is a strong metal chelator. More effective might be phosphoric acid, EDTA or sodium hexametaphosphate (Calgon) but these are not easily come by in food grade for the amateur. Prevention is better than cure. Andrew Lea.

green/blue spots

Q. I am in the process of making some cider the traditional way by letting the wild yeasts do their work and after approx 10 days of fermentation I noticed a few small spots of green/bluish mould in the froth. I then syphoned it off into carboys to let any more fermenting continue. It all tasted fine to me but should I be concerned about the mould or is it normal ? Thank you ...Adi

A. Of the 8 batches of cider we have this year, the only one we didn't sulphite developed the same blue/green mould spots in the early stages of fermentation. Since this was a high acid juice we felt sulphite was not neccesary, but it would seem this isn't the case. We skimmed the head, racked into a clean fermenter and made sure it was well topped up. The cider is now fine, and the alcohol level should keep it free from any repeat of mould growth. Mark

A. Did you use an airlock? Free access to air will permit mould growth. Under an airlock CO2 builds up and mould cannot grow. For this reason an airlock should be employed as soon as possible after the initial froth subsides. Ten days is far too long. Two days max is more like it, I would suggest. Ideally an airlock should be in place from the very beginning but it can get quite messy. Cotton wool is an alternative disposable closure stopper for the first day or two. Andrew Lea

Additives

Sweetening

  • Q: How can I sweeten my cider?

A: Many would ask: "Why would you want to?" - but sweetening is good for hiding faults such as over-acidity, as well as (potentially) making it more accessible... This is perhaps why many "industrial ciders" are quite sweet when compared with a high-juice, natural, craft-made product.

Adding sugar to a draught cider is perhaps the most simple, and least controversial way of sweetening a dry cider, but is only really suitable if the cider is to be sold/drank within a matter of days rather than weeks, since the cider will eventually start re-fermenting with the potential for cloudiness, unusual flavours etc, and loss of sweetness as the sugars are fermented out. In the case of bottled ciders, the addition of sugar is best avoided, unless carefully measured for the production of a 'Champagne' style cider, using an appropriately strong bottle; or the cider is subsequently pasteurised to render it stable. Sweeteneing a cider destined for bottling without these precautions could lead to a dangerous level of CO2 production, and the potential for popping corks at best, and exploding bottles at worst.

Aspartame-based sweeteners such as 'Canderel' are non-fermentable, but break down quite quickly when in the presence of alcohol and the sweetening effect is lost within a week or two, so OK for short term serving. Saccharin is the most common and surprisingly widely-used sweetener as this is unaffected by the alcohol, but it is said to adversely affect the taste of the product and it's use is frowned upon. Sugar-based sweeteners like 'Splenda' are also unaffected by alcohol, have no apparent adverse effects upon the taste of the cider and are non-fermentable, so are one route forward if sweetening is your aim. This sugar-based sweetener can also be obtained in it's pure form - but it is expensive, though you only need very small amounts so is cost-effective in the long run. However, even though it's based on sugar, it is still artificial and many frown upon it's use.

Keeving (as practised by the French) is another non-artificial way of making a sweeter cider but has to be carried out before starting off the fermentation. See the fermentation section of this FAQ for more on keeving. Repeated racking is another method that has to take place during fermentation, as does stopping the fermentation using SO2 or a commercial 'fermentation stopper' when the required sweetness / SG is reached. However, stopping the fermentation again involves using more artificial means and chemicals.

Pectic enzyme

Q I'm pressing some apples which have been stored for a while. Do I need to add pectic enzyme to avoid haze?

A You only really need pectic enzyme if you are using dessert fruit rather than cider apples or perry pears and you must have clear cider. Cider fruit usually 'drops bright' on its own. If you have really awful dessert fruit that oozes through the press cloths then it's certainly worth treating the milled pulp with enzyme overnight, just to help with pressability as much as with post-fermentation haze.