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THE SCIENCE OF CIDERMAKING

Part 2 - Fruit and Cultivation

This section is aimed at the cidermaker who plans to grow his own fruit. I have assumed that he is planting up from scratch but already knows something about apple cultivation, or is able to read up the subject from one of the excellent books on dessert apple growing (such as Harry Baker's 'The Fruit Garden Displayed' published by Cassell for the Royal Horticultural Society - now out of print).

To decide what cider fruit to grow we need to know a little about fruit composition. About 80% of the apple is water soluble in the form of juice, and the approximate composition of that juice in different varieties is shown in the table below.

The Composition of Apple Juice 

[Figures in percent by weight] 

Component
Bramley
Cox
Typical bittersweet
Ideal cider apple
Sugar 10  12  15 15
Malic acid > 1 0.5 < 0.2 0.4
Tannin < 0.05 0.1 > 0.2  0.2
Amino nitrogen 0 - 300 parts per million depending on cultivation
Starch 0 - 2%, depending on fruit maturity
Pectin 0 - 1%, depending on fruit storage period

 

For reasons which will become apparent in a later section, the composition of the 'ideal' cider juice should be similar to the figures in the last column. Unfortunately, very few 'true' cider apples match this ideal, and therefore a blend of cider apples is nearly always necessary. A renowned cultivar that does approximate to the ideal is the bittersharp 'Kingston Black', but this is scarcely grown commercially nowadays on account of its susceptibility to canker. It has become more usual to plant a range of bittersweet varieties, using 'sharps' to balance the acidity or, more commonly these days, using 'Bramley' which always seems to be readily available. There is some merit, in any case, in not putting all one's eggs in the same basket as far as cider varieties are concerned.

Vintage Quality

In addition to the figures quoted in the Table, there is another elusive characteristic which can only be described as 'vintage quality'. There is no clear understanding of what this means in chemical terms - it is probably due to minute amounts of certain flavour precursors or possibly the presence of micronutrients which cause the fermentation yeast and bacteria to act in particular ways. Nevertheless, there is general agreement that certain cultivars produce a superior quality of cider to others, even though they may not give the highest yields nor be the easiest to grow. The same is true of wine-making - in France for instance the 'Cabernet Sauvignon' is rated a far superior red-wine grape than is 'Carignan', although of course soil type and climate also play a major role. An apple successful in one area may perform indifferently in another.

Not all 'true' cider apples necessarily produce 'vintage quality'. The cultivar 'Michelin', which is widely planted for cidermaking in Hereford and Somerset, is a good example of this. As a sort of 'Golden Delicious' of the cider world, it is easy to grow and to process but provides mere bulk without any distinction. A list of high quality cider cultivars is given in the Table below.

Vintage Quality Cider Apple Cultivars 

Name
Growing Habit
Flowers
Harvest
Comments
Sharps
FREDERICK  Growth moderate, light crop, drooping and awkwardly placed growth  Early/mid  mid Oct Very fruity and characteristic high quality, but may not store long
BROWNS APPLE Vigorous, tends to biennialism Mid/late end Oct Fruity aroma
CRIMSON KING Large triploid Mid mid Oct Large fruits but better for cider than Bramley
Mild bittersharp
KINGSTON BLACK Growth and cropping moderate. Slow to start bearing Mid mid Oct Excellent distinctive flavour, allegedly the 'perfect' cider apple!
Medium bittersharp
BROXWOOD FOXWHELP Growth moderate, biennial  Early  Sept/Oct Full body, good blender
DYMOCK RED Moderate, spreading, biennial Early  Sept/Oct Good allround bittersharp
STOKE RED Slow and very twiggy  Mid/late end Oct Fruity aroma, high quality, for single variety cider or blending
Medium bittersweet
DABINETT Small tree, precocious but grows neatly. Needs high potash Mid/late end Oct/Nov Soft but full-bodied tannin. A "must have" for behaviour and blending!
MAJOR Growth spreading. Annual cropper Mid end Sept Excellent soft tannin
YARLINGTON MILL Tends to droop. Good biennial cropper Mid  Nov  Good light aromatic cider
Full bittersweet
ASHTON BROWN JERSEY Moderate growth, spurs well. Good yields but biennial Mid/late Nov Pronounced hard tannin
HARRY MASTERS JERSEY Compact, good annual cropper  Mid/late end Oct/Nov High sugar, high tannin but fruit may not store
MEDAILLE D'OR  Smallish tree, wood tends to split. Strongly biennial Late  end Oct/Nov Very high but 'soft' tannin
Sweet
SWEET ALFORD Strong annual cropper, tip-bearer and prone to scab Mid  end Oct High sugar, good bulk for fermentation
SWEET COPPIN  Strong large tree. Mildew susceptible and biennial  Mid end Oct Good allround sweet

Generally it is considered wise to grow a selection of cultivars to hedge your bets. If you live in a traditional cider-growing area, you may already know which cultivars do best in your locality and so you may decide on these. Otherwise, you can plant a few of each and assess them as time goes on. At worst, you can always 'topwork' over the poor varieties to the better ones in later years. But do bear in mind the ultimate blend of fruit you need - a cider made entirely from heavy bittersweets may have insufficient acid and too much tannin to produce good cider, unless you blend it with the ubiquitous 'Bramley' or with synthetic malic acid from a bag!

Remember also considerations like the fruit harvesting period. Few small cidermakers can have a need for the early cultivar 'Nehou', whose fruit is ready in late August but which bruises easily and does not store. As with dessert apples, mid- to late-season varieties generally store better and produce superior quality ciders.

Location and Shelter

For orchard location, the same considerations apply as with dessert apples. Cider apples tend to flower late, so frost is not usually a problem, although overt frost pockets are best avoided. Ensure that all your trees will find a pollen partner locally by matching flowering times, or plant a few Malus crabs as pollinators to ensure this. Depending on exposure, a windbreak might be useful. For a small site, fast growing willows such as Salix 'Bowles hybrid' will reach 12 ft in 3 yrs when planted from cuttings through black polythene, and can be trimmed annually thereafter. Evergreen cypress 'Leylandii' is also another possibility, perhaps interplanted with alder Alnus cordata to provide a semi-permeable screen which is more efficient than a solid wall of vegetation. Early-leafing hybrid poplars (e.g. TxT 32) should only be used on the largest sites, since they are greedy feeders. Hawthorn hedges are best avoided since they are alternative hosts to the 'fireblight' bacterium Erwinia amylovora which sometimes affects cider plantations.

Spacing and Yield

Tree size is an important consideration. Most people nowadays go for a semi-intensive bush orchard e.g. on MM106 rootstock at 12 - 15 ft spacing or on M26 at 8 - 12 ft spacing. If the soil is poor, go for the MM106 or even MM111. These trees should start to bear after 3 - 4 years and will bear fully from year 10 - 25. If you take a longer term view, and you have space for a truly traditional orchard as a landscape feature, go for standard trees on M25, spaced 30 - 40 ft apart. They may take a decade to come into bearing, but will go on for a century thereafter! (Author's note: Consider a quincunx' planting plan in a dwarf orchard, which will allow you the possibility of strategic tree removal in future years if they get too big. I didn't do this and I regret it!!)

A reasonable yield for all trees is an average of 5 tons per acre, but this can vary hugely due to biennial bearing ('on' one year and 'off' the next) and to the extent of fertiliser application. In commercial cider orchards, 120 lbs/acre of N and 80 lbs/acre of K is typically applied annually, perhaps with the addition of phosphate and magnesium. The actual levels required are often determined by leaf and soil analysis. In an organic system, FYM might be used instead. For high quality cider, it is undesirable to feed the trees more than is absolutely necessary, and it is particularly important not to apply excess nitrogen. Yield may go up but quality certainly comes down, and there is ample evidence that the best ciders are produced from orchards low in nutrients. Aim to keep your trees just healthy, but not in the 'lap of luxury'!

Buying and Planting the Trees

Obtaining the stock and planting it follows normal orcharding practice. However, there are only a few specialist nurseries selling cider trees and you may have to wait for them to be grafted (budded) to order onto the rootstock you want. It is always best to start with maiden trees so you can train them properly from the start. Make sure you get virus-tested EMLA rootstocks and scions. Although traditional orchards were usually virus-ridden, there seems little point in repeating this tradition now that healthy stock is available. If possible, pit-plant trees individually with plenty of organic matter and bonemeal - good preparation is never wasted. They will need good stakes and rabbit/hare guards, certainly for the first few years of life.

The best orchard floor is grass, although the immediate base of the trees should be kept clear of vegetation. If sowing a new sward, a slow growing mixture of chewings fescue (60%) and browntop bent (40%) has recently been recommended, or a slow-growing perennial ryegrass (sports turf mix) may be used. Some growers like to add white clover for its nitrogen fixing abilities. The grass should be cut as frequently as required, with the mowings allowed to rot in situ or used as a mulch at the base of the trees. Grass should never be removed from the orchard because this can lead to severe potassium deficiency and subsequent defoliation. A final cut can be made just prior to harvest, so that the fruit has a short clean sward on which to fall. You can run livestock e.g. sheep in traditional orchards although the tree trunks must be well protected by fencing. This is more difficult in bush orchards since both trunks and lower branches are vulnerable to browsing. As the trees mature, however, the lower tier of branches can be removed to allow for grazing if required. Chickens are an excellent alternative to sheep in dwarf orchards (and they greatly enjoy the blossoms on the lower branches!). Livestock should always be removed a couple of months before harvest to reduce the risk of bacterial contamination of fruit by animal droppings (author's note: I don't actually remove my chickens, but I DO wash my fruit throroughly!).

Pruning and Management

Pruning of bush cider trees is rather different from that of dessert apples. There is no need to go for the 'open goblet' shape, pruning of laterals etc. - in fact, pruning should be fairly minimal. Fruit size and finish is not tremendously important, and hard pruning of most cider varieties tends to stimulate excessive growth and can encourage biennial bearing. Current commercial practice favours a 'hedgerow wall' which is really designed for convenience during spraying and mechanical harvesting of the fruit. For the smaller grower, the objective should still be to maintain a good central leader with fruitful side branches as near horizontal as possible, although not all cultivars will respond equally readily to this ideal.

At planting, prune the maiden tree to a good bud about 3 ft above ground level, rubbing out the two buds below as they break in spring. Existing side branches ('feathers') below 2 ft should be cut off flush with the stem, but those above 2 ft may be retained as part of the first tier of permanent branches. In subsequent springs, the leader may be tipped slightly back to a good growth bud and the two buds below should be rubbed out. This will help more horizontal laterals to break further down, and reduce competition with the leader. Branches that do begin to compete vigorously with the leader should be cut out during the summer. Do not allow more than 2 side-branches per 4 ins vertical run of stem. In autumn, it will be worth tying down any upward pointing side-branches to a more horizontal position. Not only will this increase their fruitfullness by reducing their vigour, but by developing wide branch angles it will prevent them splitting under heavy loads when carrying fruit later.

Pests and diseases of cider trees are similar to those of dessert fruit, although the severity of attacks may be less. Scab and codling moth damage are scarcely important to the cider maker unless extremely severe, and even large cider growers may only spray routinely against mildew. Frequently, no spraying at all is required and cider apples are therefore well suited to organic cultivation. Fireblight, though, is a potential problem and is spread from blossom to blossom by pollinating insects which carry the bacterium. There is no easy solution and affected limbs should be cut out and burnt as soon as the disease is noted. MAFF should also be informed.

Biennial bearing is perhaps the biggest single headache for the cider grower. It is caused by a large crop in one year (the 'on' year) supressing flower-bud formation for the next year (the 'off' year). This pattern is often set by external climatic factors, such as a warm summer, so that all the trees in a locality tend to go 'in phase' with each other. For the UK as a whole, there is a strong biennial trend. For instance, crops in the years 1980, 82, 84 were about twice those in 1981, 83, 85. This is one of the factors which has led many manufacturers to rely so much more on concentrated juice to even out supplies from year to year. There are various potential remedies for biennial bearing, mostly using hormone sprays to control flower bud initiation, or even using hand removal of part of the blossom in an 'on' year to ensure some crop in the subsequent 'off' year. However, most growers are understandably reluctant to substitute less 'jam today' for an uncertain 'jam tomorrow'!

Harvesting

Cider fruit should never be harvested until it is fully ripe and it is usual for much of the crop to fall on the floor before harvesting commences - the tree can be shaken to bring down the rest. Large growers use tractor mounted tree shakers, air blowers and mechanical brushes to sweep up the fruit from the orchard alleyways. This can cause some fruit damage but a small amount of bruising is usually acceptable. Smaller growers will usually be hand harvesting using buckets and barrows. Spiked-roller harvesters ('hedgehogs') should never be used because the tines penetrate the fruit which leads to inoculation with undesirable soil micro-organisms. The fruit should ideally be harvested into slatted wooden or plastic boxes for storage, although in large operations tipper trucks and concrete silos are used.

Once harvested, mid- to late-season fruit need not be processed at once. In fact it has traditionally been considered necessary to store the fruit up to a month or so after harvesting. The major reason for this is that starch in the fruit is still being converted into sugar even once the fruit is off the tree, and it is desirable that this process should be complete before fermentation. Changes in flavour precursors also probably occur. However, soluble pectin is also produced as the fruit is stored, which may eventually cause problems of sliminess when the fruit is being pressed. So it is unwise to store the fruit for too long - two to four weeks is probably a reasonable period. Traditionally, the apples are ready for milling when they retain the impression of a thumbprint after squeezing in the hand! You can also use the 'iodine test' to check for the presence of residual starch.

Before milling, fruit should be washed to remove soil, dead insects, leaves, stones, and rotten apples. It is fortunate that healthy apples float in water (pears don't!), thus providing an easy way to wash and clean the fruit. Clean water should be used to wash each batch of fruit - if the water is recycled, the dirt is recycled too! Don't be afraid of washing away the yeast - you won't! It is a popular fallacy that desirable fermenting yeasts are present on the fruit skin. There are indeed some types of yeast on the skin and in fact there can be up to 45,000 yeast cells per gram of fruit actually inside the apple itself, which get there through the open eye (where the flower petals once were). However, scientific study has shown that these yeasts (species such as Kloeckera and Candida) have only weak fermenting power and they soon die in more than a couple of percent of alcohol. They are not the Saccharomyces yeasts which are required for the successful completion of fermentation.

In a traditional cider-making operation where no yeast is apparently used, the inoculum resides on the press racks, the cloths, the vats, or even on the walls and ceiling. It persists from season to season but virtually none of it comes from the apples. Wild Saccharomyces yeasts are not very common, so this inoculum can take several years to build up but, once established, it can determine the 'house flavour' of a particular product. It is largely a matter of luck whether this flavour is desirable or not. We return to the subject of yeasts in a later section.

 Andrew Lea 1997. Lightly updated 2009

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