page is organised into several sections. The principle
stages of the fermentation are described, followed
by an overview of the cider making
process, a discussion of the characteristics
of the apple juice, the microbiology
of the process, the changes
in the composition of the cider during fermentation,
and finally a description of how
to make your own cider.
be put off by the technical detail, you don't need
to know any of it to make your own high quality
cider - just skip direct to the home
cider making section, but if you are interested,
I hope that this document satisfies your curiosity.
There's a further reading section at the end if
you want to know more.
While the current editorial team will be more than
glad to have your feedback; please be aware that
this was written by Gillian Grafton not by the current
editors! This document is as accurate as Gillian
made it, but you're on your own - we don't accept
any liability for the contents!
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is made from apple juice which has undergone two
different kinds of fermentation. The first fermentation
is carried out by yeasts which have either been
added deliberately or which are naturally present
on the apple skins. This fermentation converts sugars
to ethanol and the higher alcohols (fusel alcohols).
The second fermentation, the malo-lactic fermentation
converts L(-)-malic acid to L(+)-lactic acid and
carbon dioxide. This fermentation is carried out
by lactic acid bacteria which are present in the
apple juice and also in the area in which the fermentation
is carried out. The malo-lactic fermentation can
occur concurrently with the yeast fermentation but
more often it is delayed until the fully fermented
cider reaches 15 C, normally in the late spring
or early summer of the year following that in which
the cider was made.
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Cider Making Process
cider making starts with the picking of the apples.
These are left to mature for a week and then tipped
into a "scratcher" which crushes the apples. In
more modern plants the apples are reduced to a pulp
in a grater type mill made of stainless steel. The
apple pulp is known as the pomace or pommy
the pulp must be crushed to extract the juice. This
is done in a cider press. Several types of press
are used. The traditional type is a rack and cloth
press (sometimes known as a pack press). In this
type of press a sheet of sisal or hessian is placed
across the bottom of a square frame above a trough.
A layer of pomace, 4-5 inches deep, is poured onto
the hessian. The hessian is folded over the pomace,
completely enclosing it. Another sheet of hessian
is placed on top of the first and the process repeated
until the layers fill the frame. The cider press
is then racked down onto the layers and the juice
runs into the trough. The pomace is pressed until
it is solid and no more juice runs out. The press
is then racked up, the layers of pomace are broken
up by hand, and the whole lot is re-pressed. In
modern plants mechano- hydraulically operated plate
presses are used. The pressed pomace is either dried
in hot air to 12% moisture and used for manufacture
of pectin, or it is directly sold on for cattle
freshly pressed juice may be fermented straight
away. In some commercial operations it is concentrated
and stored for later conversion to cider, in which
case it is extensively treated to pasturise it and
to remove pectin. The fresh juice may be fermented
in one of two different ways. Traditionally the
juice is run into a wooden pipe (a barrel which
can contain 120 gallons) or smaller wooden barrels,
and the bung of the barrel is removed. No yeast
is added, traditional cider making relies on wild
yeasts. The fermentation starts in 1-2 days and
continues for several weeks, during which time the
barrel is topped up with more cider. When fermentation
is over, the bung is replaced and the cider matured
for 5-6 months.
the juice is treated with sulphur dioxide to inhibit
natural wild yeasts, and is then fermented with
added pure yeast cultures. This method is used in
high output commercial operations. After the initial
fermentation subsides, the cider is left for the
yeast to settle, and it is either racked and/or
centrifuged and placed into storage tanks. Storage
may last 12-18 months, and the cider is blended
with new and old ciders to moderate any excessive
changes thus maintaining a consistent flavour profile
year on year. These cider blends are nearly always
cleared by centrifugation or kieselguhr filtration.
This type of cider is sterilised by sterile filtration
or flash pasteurization and is artificially carbonated
in the bottle by counter-pressure bottle fillers.
Sulphur dioxide is added at this stage to maintain
the stability of the cider. The resulting product
may be considered analagous to keg beer.
cider is often served completely flat and may be
cloudy. It may also be served a naturally-conditioned
cask cider, analagous to real ale. In France, cider
is produced by the Charmat process (oten used to
produce sparkling wines) and is highly carbonated
and more like an apple wine than traditional English
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of Apple Juice
to wort, apple juice has a much lower pH, a much
lower soluble nitrogen content, and a virtual absence
of any sugars other than mono- and di-saccharides.
The composition of the juice varies with the apple
variety used. The average composition of cider apple
juice in terms of its sugar content is 74% fructose,
15% sucrose, and 11% glucose. There are almost no
other sugars present so that there is very little
residual gravity left in fully-fermented ciders.
major acid present is L(-)-malic acid but shikimic,
quinic, chlorogenic and p-coumarylquinic
acids are commonly present. The juice also contains
soluble pectin (polymers of galacturonic acid esterified
with methanol). Tannins are present, mainly epi-catechin,
dimeric and trimeric pro-anthocyanidin and phenolic
acids. These phenolics are the fraction which undergoes
oxidation in damaged fruit.
soluble nitrogen content is low and is largely made
up of asparagine, aspartic and glutamic acids. Apple
juice usually contains one eighth of the soluble
nitrogen content of wort. The lower nitrogen content
is further exaggerated by the much lower pitching
rates used in cider making when compared to beer
making, usually 5-15 times lower. This means that
the apple juice must support a higher degree of
yeast growth and thus the fermentation is much protracted.
Some commercial operations now add ammonium sulphate
to the cider to give rapid and consistent fermentations.
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Microbiology of Apple Juice
apples have less than 500 yeast-like organisms per
g of sound fruit. The main organisms are Aureobasidium
pullulans, Rhodotorula spp., Torulopsis, Candida,
Metschnikowia, and Kloeckera apiculata.
Saccharomyces species and other sporulating
yeasts are rarely found. Acid-tolerant bacteria
such as Acetomonas spp. are usually present.
Lactic-acid bacteria are rare. The amounts of micro-organisms
rise if the fruit is allowed to fall naturally or
particularly if the skin is damaged. Yeast counts
rise due to the indigenous flora of the factory
in which the apples are processed. The traditional
rack and cloth press is also a major source of contamination.
juice cannot be sterilised by heating since the
pectin esterase enzymes in the juice are destroyed
by heat, thus the resulting cider will not clear.
Addition of sulphur dioxide is the most common way
of controlling unwanted organisms. The amount of
sulphur dioxide needed depends on the pH of the
juice. Between pH 3.0 to 3.3, 75 ppm is needed,
between pH 3.3 and 3.5 100 ppm is necessary and
150 ppm between 3.5 and 3.8. In the UK the maximum
legal limit for sulphur dioxide is 200 ppm and this
may well be lowered by subsequent legislation. Always
check with your local authorities! The sulphur dioxide
can be added in the form of Campden tablets. The
juice is left overnight to allow the different forms
of dissolved sulphur dioxide to equilibrate. Aerobic
yeasts, and lactic and acetic acid bacteria are
generally destroyed. The activity of other yeasts
is usually inhibited. If there were substantial
amounts of rotten fruits used to make the juice,
compounds present in these fruits such as 2,5-D-threo-hexodiulose
and 2,5-diketogluconic acid will strongly inhibit
the action of the sulphur dioxide. As well as preventing
infections, the sulphur dioxide also has an anti-oxidant
function producing a cleaner flavour. This is not
necessarily an advantage, the use of sulphur dioxide
has led to sweeter ciders with a loss of the apple
character in the flavour.
malo-lactic fermentation is carried out by non-slime
forming strains of Leuconostoc mesenteroides,
Lactobacillus collinoides and very rarely
Pediococcus cerevisiae. These bacteria are
readily inhibited by the levels of sulphur dioxide
used in cider making yet ciders readily undergo
malo-lactic fermentation in the spring/summer after
they were made. The explanation for this is not
certain, possibly lab strains of these organisms
are more sensitive to sulphur dioxide than are wild
strains, possibly the sulphur dioxide merely inhibits
the bacteria and they subsequently recover, or possibly
there are other organisms at work.
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in Apple Juice Composition During Fermentation and
majority of this section refers to ciders fermented
with naturally occurring yeasts. It is assumed,
but not known, that similar process occur when fermentation
with pure cultures is used.
the end of the yeast fermentation, yeast release
nitrogenous compounds into the cider. These include
amino acids and peptides. Pantothenic acid and riboflavin
are also released along with some phosphorus compounds.
The release of nutrients is important since it is
necessary for the malo-lactic fermentation to occur.
the yeast fermentation there is an increase in acidity
due to the formation of L(- )-malic acid by the
yeast. Gluconic, lactic and succinic acids are also
formed. Mono- di- and tri-galacturonides are present
from the enzymic degredation of pectin, and keto
acids are also formed. Higher or fusel alcohols
are formed; unlike beer where they are unwanted
compounds, in cider they form important components
of the flavour profile. The levels formed depend
on apple variety, juice treatment, yeast strain,
fermentation conditions, and storage conditions.
In general, low pH and low nitrogen levels tend
to produce ciders with higher fusel alcohol levels.
Use of sulphur dioxide, and centrifugation of the
apple juice before fermentation both result in the
lowering of fusel alcohol levels. The factor most
affecting fusel alcohol levels is the strain of
yeast. Aeration is also a factor, aeration reduces
fusel production markedly.
maturation phase of cider production includes the
malo-lactic fermentation. In this stage, malic acid
is converted to lactic acid and carbon dioxide.
The exact type of acid produced depends on pH. At
pH 3.6 more lactic than succinic acid is produced,
whilst at pH 4.8 only succinic acid is produced.
The nearer the pH is to 3.0, the more delayed is
the onset of the malo-lactic fermentation. As well
as the conversion of malic to lactic acid, this
fermentation also sees the production of quinic
and shikimic acids both of which are essential for
a good flavour balance.
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pick your apples. They should be fully ripe, windfalls
are excellent. Do not use heavily bruised or damaged
apples. After picking, keep in a cool place for
1-2 weeks to soften the skins. Do not wash or sterilise
the apples if you wish the cider to be fermented
with wild yeasts. You can perform this step if you
want to ferment with a specific yeast strain, however
treatment with sulphur dioxide (see below) will
get rid of wild yeasts. If you have apples which
have small amounts of damage you can cut these parts
out, but it is not essential and many traditional
cider makers avoid this step.
matured the apples, you will need to press them.
A domestic fruit juicer will achieve this but I
know from bitter experience that this is a laborious
time-consuming process, and the return in terms
of juice per pound of apples is poor. Much better
to buy yourself a wine makers fruit press, the sturdier
the construction the better. Alternatively you can
build your own cider press.
the juice is separated from the pulp you must check
the pH. If the correct balance of apple varieties
is used, this step may be omitted. Few of us are
fortunate enough to obtain the correct types so
some compensation must be made to ensure that there
is sufficient sharpness but that it is not overdone.
pH should be in the range 3.9 to 4.0. To lower the
pH add malic acid (the principal acid in cider).
To raise the pH add precipitated chalk. 1 tsp of
pectolase per gallon of juice may be added at this
stage to ensure that the cider clears. Traditional
ciders shun this step and some can look like cloudy
apple soup. Never fear, they still taste great.
a correct balance of cider apples has not been available
it may be that you need to compensate for a lack
of sweet apples. Only experience with the particular
varieties available to you will tell. Measure the
O.G. (this may be difficult if the juice was not
sufficiently well separated from the pulp). The
target O.G. should be around 1055. If not, add sugar
to bring it to this level. A good guide to how much
to add is 2 1/2 ounces of sugar will raise the gravity
of 1 gallon of juice by approximately 5 degrees.
You can either dissolve the sugar in a small quantity
of juice and add to the bulk of the juice, or if
very fine (caster) sugar is used, stir it directly
into the bulk of the juice. DO not heat the
juice or you will get a cooked apple flavour which
will ruin your cider.
the apple juice in a fermenting vessel. Traditionally
this is a wooden barrel. If these are not available,
any suitable wine fermenter would be fine. Put under
an airlock and leave to ferment. Cider is traditionally
fermented at whatever is the outside ambient temperature,
however, if you are fermenting with a pure yeast
culture it may be better to ferment at the temperature
specified with the culture. There are wild yeasts
present on apple skins (so long as they are from
an unsprayed orchard) which will ferment the cider
naturally. If you wish to ferment with a specific
yeast, add 1 crushed campden tablet per gallon of
juice and leave to stand, covered, for 48 hours.
This will see off the wild yeast. Then pitch with
a yeast of your choice. For a traditional style
English cider, use an ale-type yeast. For a Normandy
style cider use a wine yeast. Kitzinger, Hock, and
Champagne yeasts all give good results. The finished
product is paler than English cider and tastes closer
to apple wine than does English cider.
the gravity regularly. There is a tendency to go
on fermenting after the desired gravity has been
obtained. To prevent this, you can add a crushed
campden tablet to the cider when the desired gravity
the desired gravity is obtained, the cider is ready
to mature. Store the cider in glass carboys or other
similar container, under airlock. Cider is usually
left in outbuildings to mature. The fluctuations
in temperature are not detrimental. In the late
spring or early summer following the making of the
cider, it will undergo a malo-lactic fermentation.
This will occur when the temperature reaches approximately
15 C. This has the effect of mellowing the cider,
it will lose much of its sharpness. You can add
malic acid or acid blend at this point if the cider
is not sharp enough for your taste. Traditional
English cider is flat, no attempt is made at a secondary
fermentation. English cider may also be served slightly
carbonated analogous to real ale. The target carbonation
in this case is 1 volume of carbon dioxide per volume
of cider (partial pressure of carbon dioxide of
1 atmosphere). If the cider is to be served slightly
carbonated, bottle in beer bottles with 1/2 teaspoon
of sugar per pint of cider (dissolve the sugar in
water and add to the cider before bottling). Normandy
cider is refermented in Champagne-style bottle in
a manner similar to Champagne making and is highly
carbonated. Consult a good wine making guide for
details on how to do this.
finally - enjoy your cider!
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These are the sources used in writing
this document. You are strongly advise you to read
Making and Cider Research: A Review by F.W.
Beech. Journal of the Institute of Brewing volume
78 pages 477 to 491. 1972. Despite being published
in a technical journal this is a highly readable
account of cider making accessible to anyone although
you'll get more out of it if you have a biology
Cider by Jo Deal. Published by the Amateur
Winemaker Publications Ltd. ISBN 0 900841 45 1,
1976. This is a tremendous little book! It tells
you how to make cider, describes a cider press
you can make at home, gives you recipes for cider,
cider punches, and a terrific section on old English
food recipes using cider. There are also a couple
of good cider drinking songs. Only the brief section
on the history of cider making lets it down. I
strongly recommend that you buy this.
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