Cider vinegar
Andrew kindly included short extract from the craft cider making book about Cider Vinegar
Ray wrote: > Anyone have any advice how to make / start off cider vinegar? Ray, Below is an extract from my book http://www.cider.org.uk/book.html. Youcan buy a vinegar culture from Brouwland. http://www.brouwland.com/
Type into the search box. Beware it isn't quick and will take several weeks / months even indoors. Andrew --
Wittenham Hill Cider Page
http://www.cider.org.uk
--------------------------------- CIDER VINEGAR From a biochemical viewpoint, cider vinegar is the next step after
cider itself on the road which converts sugar through to alcohol, thence
to acetic acid and finally to carbon dioxide and water. At each step,
the organisms involved gain energy from their environment - this, after
all, is why they do what they do and their metabolism is very little
different from our own in most respects. Animals, however, do not stop
at the alcohol or acetic acid stage. Some micro-organisms do and we can
take advantage of this to provide the products that we want. Vinegar is
simply a dilute solution (about 5%) of acetic acid which results from
oxidation of the corresponding quantity of alcohol by the aerobic
bacterium Acetobacter xylinum. To make cider vinegar we need to start with a fully fermented dry cider
with a minimum 5% alcohol content. Sulphur dioxide should not have been
added, because this may inhibit the conversion to acetic acid. Contrary
to all good cidermaking practice, we then need to leave the cider in a
vessel with plenty of access to air and to ensure that acetobacter can
get in, or the bacteria may be added in the form of a 'vinegar mother'.
These organisms, fatal to good cider, are just what we need for vinegar. The traditional set-up for vinegar-making is known as the Orleans or
barrel process and consists of a barrel laid on its side, three-quarters
full of wine or cider with open access to air. The bung hole is lightly
plugged or covered with gauze so that oxygen can get in but flies
cannot! A 'vinegar mother' floats on the top of the wine and converts to
vinegar at the rate of roughly 1% per week so that a cider with an
alcohol of 6% will give a vinegar of 6% acetic acid in a couple of
months or so. The barrel must be kept warm, 20° C or above. Two-thirds
of the barrel is then drawn off as vinegar, fresh cider is added, and
the cycle is repeated. Modern vinegar factories do not use this method, because it is far too
slow. They use big fermenters (acetators) with forced aeration and a
very high population of acetic acid bacteria, which can convert a wine
or cider to a vinegar within a few hours. Efficient as the big
fermenters may be, the advantage of the barrel process is that is has no
moving parts and virtually nothing to go wrong. You just have to wait a
good deal longer! Setting up the system is the hardest part. Traditionally, a vinegar
barrel was always started by adding an inoculum of old vinegar from
somewhere else. But it will be no good for you to buy a bottle of
vinegar and hope to use it as a starter, since all modern commercial
vinegars are pasteurised and the acetobacter do not survive. If you wait
long enough, though, wild acetic acid bacteria will almost certainly
find their way in. Probably the best plan is to keep an open jar of
cider, covered with a coarse mesh, in a warm dark but airy place for as
many weeks as it takes for a 'mother of vinegar' to form. Fruit flies
may be an advantage here since they probably carry acetobacter about
with them. It is wise to add about 25% of commercial cider or wine
vinegar to the jar to inhibit other non-acetifying organisms. Make sure
that the vinegar you add does not contain any SO2 or other preservative
- this will be stated on the label. It is now possible to buy a starter of vinegar bacteria from at least
one winemaking supplier. Although I have not used a commercial starter
myself, since I have had my own culture going for 25 years (and
counting!), I would imagine this would soon form a 'mother' if allowed
to develop in the appropriate conditions. The 'mother' is simply a floating jelly-like mat of cellulose made by
the acetobacter themselves to keep them close to the surface, since air
is essential for their existence. Once you are sure you have a genuine
gelatinous 'mother' and not a powdery film yeast, and you can really
smell the vinegar, you can pitch it into your barrel with the required
amount of still dry cider and your Orleans process will be under way.
Keep it warm, up to 30° C if you can, for best results. Another method
for generating a vinegar starter is to make a heap of fresh apple
pomace, keeping it moist and preferably warm for several weeks. During
this time it will ferment its residual sugars and natural acetobacter
should then proliferate. Once it smells quite vinegary, the pomace can
be squeezed out through a muslin bag and the resultant liquor (rich in
acetobacter) can be used as a starter which will eventually develop a
'mother'. Do not, whatever you do, use the same equipment and vessels for vinegar
making as for cider. The risk of cross-infection is just too great and
it is not worth spoiling your good cider by trying to economise in this
way. Keep both operations entirely separate! If you are making vinegar
close to your cider, as you probably will be, it is doubly important
that your cider-making kit be properly cleaned and sterilised anyway.
To know whether the vinegar is ready or not you really need to measure
the acid. You can use a winemaker's acid titration kit for this but you
must dilute the vinegar exactly ten times with distilled or deionised or
rain water before you carry out the titration. Then multiply the result
by ten. If the results from the kit are expressed as tartaric acid you
must multiply them again by 0.8 to express the result as acetic acid.
The minimum amount of acetic acid required by EU food law for sale as
vinegar is 5%. Once the vinegar is made it can simply be run into bottles for use. On a
domestic scale there is no need for pasteurisation. Cider vinegar from
the Orleans process is generally fairly clear but it may develop a
further haze on storage in bottle. This is due partly to renewed growth
of bacteria and partly to polymerisation of tannin. You can fine the
vinegar with gelatin/bentonite if necessary to reduce an existing or a
potential haze. If it is then important to prevent further clouding, SO2
at 50 ppm (i.e. 2 Campden tablets per 10 litres) may be added just
before bottling, and this will inhibit both types of spoilage process.
Vinegar vats occasionally become infected with vinegar 'eels'. These are
small and transparent nematode worms a few millimetres long, which live
on the acetifying bacteria and which wriggle ceaselessly at the top of
the vat. Although quite harmless they are generally unsightly and people
do not like them. They may be destroyed by heating the vinegar to about
50° C, followed by fining or filtration after cooling. Or you can just
leave them as a talking point for your guests - they will liven up any
salad dressing!
