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FAQ.
Q.
MY WINE HAS NOT STARTED TO FERMENT ?
This may or may not
be true. What you are really saying is " I am not seeing bubbles
pass through my airlock."
The wine could in
fact be fermenting but the fermentation gas (co2) is escaping from
somewhere other than through the airlock due to an ineffective seal.
How can we confirm
this?…
Simple, the only true way of checking fermentation progress is by
using a hydrometer. Take three specific gravity readings over a
period of 24 -36 hours. If these readings are the same then we can
safely assume that fermentation has not started. If the readings
are coming down then fermentation is taking place. In this case
there is no need to worry.
Let the wine ferment
until the desired specific gravity is reached and finish it off
accordingly. However, if fermentation has not started then we need
to get it going by adding fresh yeast. This is a little more tricky.
We need to identify the cause of the problem and remove it. It is
a process of elimination.
Why has fermentation
not started, is it the yeast?…
Yeast is a living
organism and can very quickly lose its viability if it is subjected
to adverse storage conditions i.e. damp, prolonged excessive heat
or direct sunlight. The yeast may have been fine when packaged but
if it has lost its viability unfortunately this only becomes apparent
when we come to use it. Get into the habit of starting the yeast
off in a glass or cup initially to ensure that it is working. This
way we know that if there is no ferment after it has been added
to the wine "must" it is not the yeast that is causing the problem.
What other reasons
could there be?…
A common cause of
non-fermentation is temperature during primary fermentation. If
the temperature is too cold the ferment becomes very sluggish almost
to the point of not working. Usually if you give the " must" a good
stir and move it somewhere warmer the ferment picks up.
Yeast cannot tolerate
long periods of heat so if the temperature becomes too hot the yeast
cells are killed. The aim is to put your fermenting vessel somewhere
not too cold, not too hot and where the temperature remains fairly
constant as fluctuating temperatures also affect the performance
of the yeast.
If your kit is one
where sugar has to be added, determine if all the sugar has completely
disolved . Un-dissolved sugar will clog the yeast cells and
inhibit them from doing their job.
After you cleaned
your fermenter did you thoroughly rinse all the sterilising fluid
away? It could be that the presence of sodium metabisulphite is
inhibiting the yeast cells.
Have you actually
added yeast? This might sound stupid but it has been known to happen.
Remember, viable yeast added to a combination of grape juice, sugar
and water would produce ferment. If fermentation is not apparent
use your hydrometer to confirm.
Identify the cause
· Remove it · Add fresh yeast if necessary
Q. MY WINE STARTED
TO FERMENT BUT STOPPED AND IT TASTES SWEET ?
Any wine where fermentation
ceases prematurely may be considered to be "stuck" or "sticking".
This may be the result of using old yeast, acid imbalance, nutrient
or vitamin deficiency, particularly when producing a wine made from
ingredients. However, "kit" wines specially formulated usually "stick"
for other reasons.
Most commonly, due
to fermentation temperature being too high or exposed to prolonged
periods of heat. Yeast cells die if exposed to prolonged periods
of heat. Fermentation itself gives out heat so that although the
air surrounding the ferment may appear cool enough the temperature
within the fermenter may be dangerously high.
- Infection. If
the yeast becomes contaminated, bacterial off-flavours will develop.
The bacteria will inhibit the establishment of a fermentable yeast
colony.
- Sterilising fluid
left in the fermenter will affect the yeast. Make sure that fermenters
are thoroughly rinsed before use.
- The addition of
too much sugar initially will cause the yeast cells to rupture.
- Undissolved sugar
will build up a layer of syrup at the bottom of the fermenter
and will inhibit the yeast.
Q.
How do I restart my wine ?
Before we can do
anything the cause of the "sticking" needs to be identified and
removed. Then we can add fresh yeast and everything should be ok.
However, the way in which the new yeast is introduced may mean the
difference between success and failure, particularly when re-starting
5 gallons.
Rather than add the
yeast directly to the bulk wine it is better to break the "must"
down and re-start in stages.
We suggest the following
method:
- Sterilise a demi-john.
- Fill the demi-john
to no more than half way with wine from the bulk.
- Add a small amount
of yeast nutrient.
- Add a good re-start
yeast.
- Put the demi-john
in a warm place.
When fermentation
is well underway top up to the gallon with wine from the bulk. Continue
this way until all the wine is fermenting.
Q. Why is my wine
cloudy ?
This could be due
to different causes.
- The wine might
still be fermenting.
- The temperature
could be too hot or too cold.
- The presence
of bacteria, pectin, starch or protein.
Well made wines will
clear naturally given time and it is important that they are given
time to clear. However, sometimes we need to give them a helping
hand and resort to fining or filtering. The use of a good quality
wine yeast will ensure that a firm sediment forms during fermentation
and that any subsequent movement of the fermenting vessel is unlikely
to cause "swirling up" clouding the wine.
When fermentation
is complete and the wine is "racked" it should be moved to somewhere
cooler. Do not put it into the refrigerator where the temperature
is too cold to allow the clearing process.
Try to keep temperature
fairly constant and not fluctuating.
- PECTIN - It is
reasonable to assume that pectin will be present to some extent
in wines. Prevention is better than cure. Use a pectin destroying
enzyme when adding the yeast or during fermentation.
- STARCH - Wines
made using ingredients such as bananas, grains and root vegetables
which contain starch need to treated with fungal amylase.
- PROTEIN - If enzymes
are used initially protein hazes are probable. Finings will aid
the clearing process.
- BACTERIA - Spoilage
organisms can enter the wine in several ways. Ensure that all
equipment that comes into contact with the wine is thoroughly
sterilised.
Do not keep "old"
equipment - update. Ensure fermentation starts quickly. Do not leave
the wine on the "leys" at the end of fermentation. ?
Q. I have difficulty
in getting my corks into the bottles. What is the best method of
corking?
Invariably when we
are asked this question we find that the winemaker is using a 'hand
corker,' a cheap, simple tool where the cork is inserted into the
bottle using pressure applied with the palm of the users hand. This
method of corking is usually fine when using corks that have been
pre-soaked to make them supple.
However it is not
100% effective. There are many different makes of corker available,
most are relatively inexpensive and if used correctly, will last
many years.
Young's always recommend
the use of a 2-handled or a 3-lever type of corker. These are readily
available in the shops and provide a much more reliable method of
producing an effective seal. For a few pounds more you can get a
floor standing type of corker, which will take even commercial size
corks.
In order to ensure
a good seal in the bottleneck the diameter of the cork is important.
Commercial applications use a 24mm diameter.
However, to facilitate
the use of hand corking machines in the home brew market, this diameter
has been reduced to 22mm. We know that some type of hand corkers
are still inadequate at the 22mm diameter and can only provide enough
insertion force with extreme difficulty by the operator. This is
why Young's recommend the 2-handled / 3-lever type.
Q. I have just
bought some corks which say 'do not soak' on the packet. What would
happen if they were soaked?
These corks have
been treated with an approved silicone material in order to facilitate
easier corking. It is not necessary to soak these corks prior to
use. If they are soaked a 'milky' residue rubs off and this can
be imparted to your wine. Although totally harmless, this residue
looks unsightly. It will settle given time and 'racking' or filtering
helps to speed up its removal. Also, a silicone treated cork that
has been soaked will disintegrate upon extraction from the bottle.
The amount of silicone applied to these corks is a compromise between
two factors:
a) Too much
silicone used could result in the cork coming back out of the
bottle due to the reduced friction.
b) Too little
silicone used and the cork becomes too difficult to insert into
the bottle.
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