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When to pick fruit
Although the numbers of measured sugar content, acidity and pH are considerations for when to harvest,
most important are the taste and look of the grapes, seeds and stems.
During The Tamar Valley's normally cool autumn, 4 to 7 days after the numbers are right,
some very intense aromatic flavours reveal themselves in Pinot Noir.
If you cut a berry open and inspect the seeds, they should be an even toasty brown.
Any greenness in the in the seeds is a sign of under ripeness or uneven ripening.
Similarly the stems should be showing a nice tan.
If you can catch these factors in your wine grapes you are picking at an optimum time.
Unfortunately in many seasons you will need to compromise due to weather or berry burst
resulting in wasp attacks or rain which dilutes the sugar levels.
As the sugar content of the grapes rises, the titratable acidity ( Tartaric Acid) falls and the pH rises.
Optimum harvest day occurs when these 3 factors are balanced.
To test Tartaric Acid see here.
Jeff Cox in his excellent book "From Vines into Wines" also suggests a method of determining ripeness
when Brix times pH - squared equals 260 for red wine grapes and 200 for whites.
Multiply pH by itself , then multiply by degrees Brix.
e.g. 24 Brix at 3.3 pH = 3.3x3.3x24= 261.36 or for whites e.g. 20 Brix at 3.2= 204.8
Both these levels are excellent for wine making, so as long as the seeds are toasty brown - GO for it.
You can use the table here to calculate your potential alcohol from the specific gravity of your grape juice.
most important are the taste and look of the grapes, seeds and stems.
During The Tamar Valley's normally cool autumn, 4 to 7 days after the numbers are right,
some very intense aromatic flavours reveal themselves in Pinot Noir.
If you cut a berry open and inspect the seeds, they should be an even toasty brown.
Any greenness in the in the seeds is a sign of under ripeness or uneven ripening.
Similarly the stems should be showing a nice tan.
If you can catch these factors in your wine grapes you are picking at an optimum time.
Unfortunately in many seasons you will need to compromise due to weather or berry burst
resulting in wasp attacks or rain which dilutes the sugar levels.
As the sugar content of the grapes rises, the titratable acidity ( Tartaric Acid) falls and the pH rises.
Optimum harvest day occurs when these 3 factors are balanced.
To test Tartaric Acid see here.
Jeff Cox in his excellent book "From Vines into Wines" also suggests a method of determining ripeness
when Brix times pH - squared equals 260 for red wine grapes and 200 for whites.
Multiply pH by itself , then multiply by degrees Brix.
e.g. 24 Brix at 3.3 pH = 3.3x3.3x24= 261.36 or for whites e.g. 20 Brix at 3.2= 204.8
Both these levels are excellent for wine making, so as long as the seeds are toasty brown - GO for it.
You can use the table here to calculate your potential alcohol from the specific gravity of your grape juice.
Harvest
Having prepared all your equipment and sterilised it, you are now ready to pick your grapes.
It is wise to wear rubber gloves if you have experienced wasps in your vineyard as their sting is quite painful.
It seems also that some people have severe anaphylactic reactions to wasps stings,
so it is wise to have an anti- histamine cream available in case of stings.
Cut the bunches and drop them into a bucket, then transfer them to the crushing area. Process the grapes through the crusher and add Potassium Metabisulphate (KBMS)10% solution to 50ppm by the table below:
or download a calculator here
It is wise to wear rubber gloves if you have experienced wasps in your vineyard as their sting is quite painful.
It seems also that some people have severe anaphylactic reactions to wasps stings,
so it is wise to have an anti- histamine cream available in case of stings.
Cut the bunches and drop them into a bucket, then transfer them to the crushing area. Process the grapes through the crusher and add Potassium Metabisulphate (KBMS)10% solution to 50ppm by the table below:
or download a calculator here
For different quantities, add the apprpriate amounts together to determine the correct quantity of KBMS (10% solution) to use .:
*The volumes assume 100 percent purity of the potassium metabisulphate (KBMS) and full strength of the stock solution.
You can calculate the amounts needed for any given quantity of must by summation of the values in the table above.
e.g. 40 litres of wine = 37.9 @ 50ppm = 32.9ml
+ 1.895l @ 50ppm = 1.6 ml
+ .397l @50ppm = .33ml
Total = 35ml approx
I add this to the must in smaller quantities using a pipette as soon the must quantity justifies it.
This stops oxidation of the juice and kills any natural yeast present so you then get to decide which yeast will colonise your must.
You can calculate the amounts needed for any given quantity of must by summation of the values in the table above.
e.g. 40 litres of wine = 37.9 @ 50ppm = 32.9ml
+ 1.895l @ 50ppm = 1.6 ml
+ .397l @50ppm = .33ml
Total = 35ml approx
I add this to the must in smaller quantities using a pipette as soon the must quantity justifies it.
This stops oxidation of the juice and kills any natural yeast present so you then get to decide which yeast will colonise your must.
Saigner and Cold Soak for red wine grapes
After de-stemming and crushing, and adding KBMS to the grapes,
with the juice drawn off that will have a slight blush having been exposed to the must for an hour or so
I draw off about 10% of the juice after 3 hours to intensify the concentration of skin to juice ratio,
thereby intensifying the colour and the skin aromatics extracted.
I make a Rosé from the juice drawn off by fermenting this separately.
After extraction of the 10% of juice, the must is kept cool at about 12 degrees centigrade in my cellar for 3 or 4 days
before the yeast is added. The lids are screwed on the vats lightly to keep out unwanted bacteria.
This cold soak allows maximum extraction of the skin pigments to give colour and flavour without the presence of alcohol.
If you have difficulty reducing your must to this temperature, you can place a bag of ice in the must to reduce the temperature.
Make sure the bag has no holes in it or you will end up diluting your wine as the ice melts.
Alternatively you can purchase some dry ice (frozen C02), which will act as a barrier against aceto-bacter
( vinegar bacteria) as it melts.
with the juice drawn off that will have a slight blush having been exposed to the must for an hour or so
I draw off about 10% of the juice after 3 hours to intensify the concentration of skin to juice ratio,
thereby intensifying the colour and the skin aromatics extracted.
I make a Rosé from the juice drawn off by fermenting this separately.
After extraction of the 10% of juice, the must is kept cool at about 12 degrees centigrade in my cellar for 3 or 4 days
before the yeast is added. The lids are screwed on the vats lightly to keep out unwanted bacteria.
This cold soak allows maximum extraction of the skin pigments to give colour and flavour without the presence of alcohol.
If you have difficulty reducing your must to this temperature, you can place a bag of ice in the must to reduce the temperature.
Make sure the bag has no holes in it or you will end up diluting your wine as the ice melts.
Alternatively you can purchase some dry ice (frozen C02), which will act as a barrier against aceto-bacter
( vinegar bacteria) as it melts.
Strain of Yeast and Nutrients
Various strains of yeast promote different characteristics in the resulting wine.
I use a general purpose wine yeast, Red Star Premier Cuvee and have had great success with this as it is suitable for sparkling wines as well.
You will also need to add a yeast nutrient , diammonium phosphate, to the must 12 hours prior to adding the yeast. Add ½ teaspoon of diammonum phosphate per4 litres of wine must to stimulate fermentation.
This supplies the must with nutrients essential for the growing yeast.
Without it you stand the chance of having an unhappy yeast and possibly a "stuck" fermentation.
Primary Fermentation (Red Wine)
The notes below are for the fermentation of red wine, where you wish to extract the optimum amount of skin pigment from your grapes to give colour.
Ideally the temperature of the must needs to be brought up to about 20-22C before adding the yeast.To achieve this in some areas, you may need to place an aquarium heater in your mustand regulate the thermostat to achieve a temperature of 20 °C.We are now ready to re hydrate the yeast.To do this I add equal parts of warm water at 38-40°C ( not above 43 °or below 35°) and juice from the mustto make a quantity of liquid equal to 5 to 10 times the weight of the dry yeast to be re hydrated.I use .25 gms of yeast per litre of must.SO in a must of 40 litres I re hydrate 10 gms of yeast in 100ml of liquid ( 50 ml Water +50 ml of must).Sprinkle the yeast on top of the liquid in a shallow plastic container and stir evenly until you get an even creamy liquid.The surface area of the liquid is important to allow the liquid to cool at the correct rate.Leave the yeast re hydrating in the liquid for about 20minutes then check the temperature.It should be no higher than 30 °C.Before adding the yeast to your must check the temperature.It should be no more than about 10 °C different to that of the must.This allows the yeast to be introduced without a temperature shock that could affect the viability of the yeast.When you are ready, pour the yeast liquid into the must and stir in evenly.Remember to keep the must at about 20 °C to allow the colonisation rate of the yeast to be at an optimum.As the yeast multiplies,( after about 12-24 hours) the temperature of the must will riseand a thick crust of berries will float to the surface.It is important that you keep punching this down regularly every 4-6 hoursto prevent the berries from drying out and from bacterial infection.As the fermentation gets underway, the must will give off carbon dioxidewhich will protect the wine from oxidization as CO2 is heavier than oxygen.You do not need to exclude air from your primary fermentation because of this.The CO2 being given off will do this for you.Follow the progress of the sugar conversion to alcohol regularly with your hydrometer.As the sugar in the grapes is converted to alcohol, the hydrometer reading will drop from say 1.1010 (24 Brix) at the start to 1.000 at the finishand even lower 0.992-0.995.Until it reaches this level it is not fully fermented so be patient. Small residual sugar levels (3-5%) will result in a sweeter wine.You can use the calculator here to see how your wine is progressing.
Stuck Fermentation
Should a fermentation "stick" or cease before completion, it is difficult to restart.
The problem usually occurs due to temperatures being too high during fermentation or to insufficient yeast nutrients.
I have recommended keeping the must temperature at 20° Celsius prior to introducing the yeast.
Once fermentation gets under way you will find that the temperature will rise naturally with the activity of the yeast.
You should withdraw the heater if you are using one and monitor the temperature of your must twice daily,
or every time you punch down the cap.
Make sure you punch down the cap before taking this reading as the temperature within the cap will be higher than the liquid below.
Ideally the temperature should be between 18° and 28 °C.
Higher temperatures than this could cause your fermentation to stick.
If your fermentation sticks, the following procedure is recommended:
Cool or heat your must to 20 °C (68 °F) Add a fresh, actively growing yeast starter ( Red Star Premier Cuvee is particularly known for its reliability in restarting a stuck fermentation) Add a yeast nutrient (Diammonium Phosphate (1/2 teaspoon to 4 litres) At the time of re-inoculation, aerate the must by stirring or pumping over two to three times daily for 1 to 2 days. Fermentation should resume. If after several days fermentation has not restarted, try a second re-inoculation. Whilst waiting for fermentation to restart make sure you keep the wine at the proper temperature- 20 °Celsius.
Pressing
After 7-10 days your wine should have reached a hydrometer reading of between 1.0010 and 1.0006 and colour extraction is complete.At this stage you can press the juice off the skins using a basket press or by squeezing batches of must through through several layers of washed cheesecloth.A basket press is by far the most efficient method and will result in optimum wine extraction.Without a basket press you will only achieve a yield of about 50% of the original grape weight you have picked.Using a press will return you as high as 70%.Line the press with a section of plastic fly screen to prevent grapes entering the pressed juice.Load the press up and allow the free run juice to flow from the press into a container.
Ensure you have sufficient packing blocks in the press so the press lever does not reach the top of the press as the wine grapes are compressed. If this happens you will need to release the pressure, add more blocks and resume your pressing.
I generally apply a little pressure to the press then wait for the flow to stop.The juice so extracted is free run juice and will be lower in tannin and less astringent.I keep this separate and blend it with the pressed wine at a later date.You don't have to do this, but a wine that is heavily pressed will have a higher tannin content and therefore will require more bottle aging to evenly distribute the tannins in the wine.From this stage you need to exclude air from your wine with an air lock.Ensure your containers are 90% full.I use 60 litre carboys for the storage of pressed wine supplemented by 15 litre & 20 litre glass carboys.Each is fitted with an airlock containing 10 ml of 10% sulphur dioxide solution to prevent any insect infection.One trick for filling a carboy that is not quite full is to immerse a bottle of water in the carboy to raise the level.The weight of the water will displace the wine and raise the level to exclude air.Be careful here! I am NOT recommending that you add water to your wine, simply use the water container to displace the air in the container. Sterilise it first before adding to the wine
Secondary Fermentation
The natural acids present in your wine are largely tartaric acid, lactic acid and malic acid.
Malic acid is a stronger tasting acid than tartaric acid and there is usually a higher presence of this in the wines of cooler district.
The process used to convert this malic acid to lactic acid is called malolactic fermentation.
It is accomplished by the introduction of lactic acid bacteria of the genus Leuconostoc.
I usually introduce this bacteria at this stage in the wine making before primary fermentation is fully completed,
as the higher temperatures during fermentation are most suitable for the leuco bacteria to work effectively.
See here for a Youtube explanation of the process.
Several factors can either encourage or inhibit malolactic fermentation.
Malolactic bacteria have complex nutritional requirements for growth.
These nutrients are either naturally present in wine or released into the wine by the yeast cells during alcoholic fermentation.
Thus bacterial growth is enhanced the longer the wine is left in contact with the lees (the dead yeast cells) or inhibited if the wine is separated from the lees soon after alcoholic fermentation.Other factors that inhibit bacterial growth are :
temperatures of lower than 16°C a high presence of SO2 a lower pH than 3.3
For these reasons I introduce the malolactic bacteria before the finish of the primary fermentation
and before the daily air temperatures go much below 18°C.
Because malolactic bacteria can reactivate in warmer temperature that follow in November, I never bottle my red wine before December after testing for the presence of malic acid.The danger of bottling wine before malolactic bacteria has been starved is that further fermentation will result in the emission of carbon dioxide which will make your wine spritzig at best or blow the bottle and make one hell of a mess in your cellar.
Another reason for leaving the wine until December before bottling is that I like to use minimal SO2.
The presence of SO2 in concentrations of 100ppm or more will inhibit malolactic concentration, however I do not like the use of this chemical other than at 50ppm during crush.
I never have a problem in the wine going off through bottle age. I don't keep it more than 4 years.
Aging and Racking
Now that your secondary fermentation has been started your wine must be kept free of air to develop optimum flavours.
Exposure to air during racking the wine will not affect it greatly as long as you don't splash it about.
Siphon the wine from the secondary fermentation unit into another container.
after about 3 weeks after the introduction of the malolactic bacteria.
Be careful you keep the flowing end of the siphon immersed in the wine to minimise the introduction of air.
Be careful when you get to the bottom of the secondary fermenter that you don't suck up large amounts of yeast in an endeavour to get all of the wine out.At this stage it is better to sacrifice a little wine to get most of the yeast out.Fit your plastic racking tube to a stick so that it's end is above the sediment in the bottom of the container.This way you will avoid disturbing the dead yeast cells accumulated at the bottom of the container.Once you have filled the container to at least 90% of its capacity, replace the airlock and leave your wine undisturbed for at least a month to settle down.
Oaking
A balanced flavour of french oak adds a very special quality to a red wine.
The purchase of oak barrels is usually not an option for home wine makers, as few make enough to fill a barrel, and most would not afford the cost of a new barrel or even a second hand one.
Second hand barrels are usually well used before they become available and as the wine has previously penetrated the wood thoroughly,
most of the oak flavours have been extracted.
It is possible to get them re shaved by a cooper, but I wouldn't bother with this .
For the home wine maker there is a better option; the purchase of oak chips from a home brewing supplier.
These french oak chips are usually sold in 1 kg or 500gm pkts
and can be easily immersed in the wine in stockings, to allow the flavour to be extracted by the wine.
Use fishing line to suspend the stocking in your wine as it is thin enough
to allow an air tight seal when the stopper is refitted to your container.
About 1gram of chips per litre for 3-4 weeks will impart a noticeable oak flavour to your wine.
Taste the wine each week and remove the chips when you are happy with the flavour.
Cold Stabilisation
Leaving your wine to stabilise at a temperature of 12° C or less over the winter months will cause the potassium bitartrate ( a product of the reaction between potassium and tartaric acid in the wine) to precipitate out, clarifying the wine to a certain extent and making the wine more stable once it is removed.
The wine needs to be racked at least 2 more times before considering whether to fine it before bottling.
Keep the temperature of the wine as cool as you can and stable so that the maximum amount of potassium bitartrate will drop out.
You can then rack the wine of this and clarify it even further.
If the wine is not racked, the formation of tartrate crystals when the wine is cooled before serving will make the crystals drop out and present a not so good looking wine in the glass.
Once you have gained a little experience in the winemaking process,
you may wish to undertake the challenge of making a sparkling wine.
In a cool climate district this requires grapes of a lower degree of ripeness, ( No more than 10% potential alcohol)
so in most years you will achieve this before wasps or changing weather patterns stop you from making
an acceptable table wine with an alcoholic level of 13.5% or more. Making Sparkling Wine
See here for instructions on how to make a sparkling wine.