Wine Computer Tool Notes

Index

Volume Estimate
False Wine Recipe
Sulphite
Basic Must Adjustments
Basic Juice Adjustments
Advanced Adjustments
Alcohol Measurement
Fruit Wine Composer

Tool : Volume Estimate

Purpose: Predict must volume from weight of grapes.
Inputs Required: Weight of grapes in either kilograms or pounds.
Inputs Optional: Number of days wine fermented on skins before pressing.
Predictions: Total volume of must and or wine expected for grapes of average ripeness and size..
Notes: See main page of site.

Tool: False Wine Recipe

Purpose: Making false wine from discarded grape skins following press.
Inputs Required: Estimate of volume of wine recovered from pressing (the value produced from Volume Estimate tool may be used).
Inputs Optional:
Notes: See main page of site.
Predictions: Recommends conservative amounts of water, sugar, acid, tannin and nutrient to add to produce a second fermentation on the skins. May be used with red or white grape skins.

Tool: Sulfite

Purpose: Recommends conservative amounts of potassium metabisulphite to add to must and at other critical points following fermentation.
Inputs Required: Volume of must (the value produced from Volume Estimate tool may be used).
Inputs Optional: pH (if known), wine type (color), sweet/dry (toggle), malolactic fermentation (toggle), fruit temperature, fruit ripeness, fruit condition,.
Predictions: Granular potassium bisulphite additions at crush, rack off gross lees, racking and bottling. May comment on wine's properties with respect to malolactic fermentation and organic stability when warnings are appropriate.
Tool Guide: Tool contains a discussion of some the pros and cons related to the use of metabisulfite in modern winemaking.

Additional Notes:

Granular potassium metabisulfite (or metabisuphite) makes it possible for the small-volume winemaker to make fresh (unoxidized) wines that will age well with only a small likelihood of spoiling.. Alternately, those making wine for their own consumption may wish to minimize (or even completely avoid) additives. There is no doubt that some people have a strong negative response to sulphites. These substances are common in many types of food and in the past were sometimes added in quite large amounts to wines that needed to survive the high temperatures they experience in shipping. People with specific allergies or certain medical problems (such as asthma) may need to avoid all such foods and most wines. If you suspect that you have such a problem then you need to do more than just avoid adding sulphites to the wines that you make as all wine contain some sulphite (see note immediately below). To be safe, you will also need to test (kits are available) the wines you make before drinking them !

All wines contain sulphites. Even if no sulphites are added during winemaking, wines naturally contain sulphites. This is one of the reasons why commercial wine producers carefully measure the amount of sulphite present during several steps of the winemaking process. They also avoid applying with sulphur sprays just before harvest. Sometimes there is even too much sulphite before anything is added by the winemaker ! Fortunately, you will find that this is not a very common problem. If you want to adopt some form of sulphite treatment, the tool will help you to add minimal amounts. The text provided in the tool details several reasons for adding sulfite (or not)..

Reducing Sulfite: The best way to reduce the use of sulphites is to make wines that do not need very much in order to ferment and age without spoilage. To do this, make red wines with robust amounts of tannin, alcohol and acid. Use only very high quality (no more than just ripe enough) fruit with no rot or mold. Test for pH and keep it low. Avoid exposure to air. Add nutrients to the primary fermentation and make sure the (high quality) yeast gets an early start. Make dry wines. If you do this, adding sulphite at crush time is probably not required and only very small amounts need be added when racking and bottling. The risk of using zero or very low amounts of sulfite is that your wine may oxidize or spoil before you can drink it. Wine was made traditionally for probably thousands of years without added sulphite. This is one of the reasons that in classical times Roman soldiers received a regular vinegar ration. What else could they do with all that wine that turned to vinegar by January?

Sulphite Wash at Crush Time. There is another way to sulfite at crush. Grapes delivered by truck often arrive with quite a bit of grit etc. If you are fermenting fairly small amounts you are probably carefully hand selecting your grapes anyway. This is the method that I prefer, particularly if I want to "cold soak" the grapes for a day or two, before start of fermentation. Make up a strong potassium metabisulphite solution containing about 15 [ml] (3 teaspoons) of granular bisulfite per liter. If you mix this in a gallon jug (either kind) add about 12 to16 teaspoons. When washing the grapes add about two cups (1 cup equals 250 [ml]) of this solution to each pail of water you clean the grapes in. Wear vinyl gloves (NOT latex which will contaminate the must) or the sulphite will cause skin erosion. YOU MUST THEN DRAIN THE GRAPES BEFORE CRUSHING which gets rid of the large amounts of water and most of the sulphite introduced in the washing process. The advantage of this method is that the amount of sulphite that ends up in the wine is fairly small and the entire surface of every grape has been exposed to the sulphite rather than the sulfite being dispersed into a large volume of must after crushing. This way very little sulfite becomes permanently bound to the sugars etc that are found INSIDE the grapes. If you have never cleaned grapes before fermentation, you may be shocked by how quickly dirt accumulates in the wash pail ! Just add a couple cups of sulphite solution each time you change the water.

Tool: Basic Must Adjustments

Purpose: Pre-fermentation additions to musts containing skins.
Inputs Required: Specific gravity (SG) and total volume of the must.
Inputs Optional: Total acidity of must, sugar addition, water addition, acid addition (tartaric or blend toggle), malolactic toggle.
Predictions: Rough (pre-additions) wine volume and percent alcohol. Post-additions wine volume, percent alcohol, sweetness, total acidity, sugar deficit (if any) and final SG of wine assuming fermentation to dryness.

Additional Notes:

Musts are produced by crushing fruit or grapes. Here we assume all stem materials have been removed.

Tannin is found in grape skins and in the skins of a few fruits like blueberries.,loganberries and blackberries. Wines made from certain fruits do not have significant amounts of tannin. If the wine being fermented is red, and the fruit is low in tannin, grape tannin should be added, particularly if the wine will be high in alcohol and acidity for wine stability and a balanced taste. Addition of tannin allows minimal amounts of sulphite to be added in order to provide stability. If the wine being made is white or rose, then tannin is not normally added. But in this case, to prevent spoilage and oxidation, the amount of sulphate that is added should be the correct amount for a white wine. The guidelines produced by the sulphite tool may be used. A normal nutrient addition should be made when making fruit wines. For red wines from low-tannin fruits typically one can add 1 teaspoon (5 [ml]) per every 5 liters of must before fermentation. See the fruit wine design tool for more accurate amounts to add to red wines made from different types of fruit (or mixtures). Many fruits contain pectin (especially apples). Fresh pectic enzyme may be added to prevent hazes. Use the amounts recommended in the fruit wine design tool or follow the recommended amounts (see package etc.) for the enzyme you are using.

Increasing the amount of sugar in the must will increase the juice's specific gravity (SG) and the alcoholic strength of the finished wine.

Increasing the amount of water in the must will decrease the SG and alcoholic strength and will also decrease the total acidity of the finished wine.

If total acidity has to be reduced by the addition of water, then some added sugar may be needed to maintain a reasonable amount of alcohol. Remember that at least 10 percent alcohol by volume is required to protect the wine from spoilage organisms. And the higher the alcohol level the more stable the wine will be. Remember also that wine should contain at least 6 grams per liter (measured as tartaric acid equivalent) of total acidity to prevent a dull taste and to protect against organic spoilage. White wines are more subject to spoilage and typically have a few grams more per liter (7 or above). Another type of acidity measurement is know as "pH". This is of even more importance in preventing spoilage, but in the case of pH, low values are better. Another tool (the sulphite tool) provided for calculating reasonable amounts of sulphite. It uses the pH (if available) to determine optimal amounts of this vital addition (potassium metabisulfite) which assists yeast to compete with bacteria and molds, prevents spoilage and reduces oxidation.

Increasing the amount of tartaric acid (or acid blend) with increase the total acidity of the finished wine by the amount shown. It is assumed that the must contains mainly tartaric and malic acid (the usual composition for grapes). For citrus or other types of fruit, it is better to use the fruit wine composition tool in order to find the amount of acid, sugar and water to add. This is because fruit other than grapes typically contain acids that are partly or entirely consumed by yeast in the fermentation. In addition certain other vital components such as yeast nutrients and tannins are not present in most types of fruit. Fruit wines are best made by recipes based on the experience of experts.

Each type of wine yeast has a particular level of alcohol which it can tolerate before it stops fermenting. Some special types of yeast can reach over 20 percent alcohol, particularly if the extra amounts of sugar required to do this are fed slowly into the secondary fermentation and other conditions such as nutrients, temperature and acidity are close to optimal. It is much more usual for yeast to stop fermenting at about 15 percent alcohol.

If sugar remains when the yeast stops fermenting, the wine will be sweet. Most producers of wine yeast make this information available. Ask where you buy your yeast if this information is not available on the package. Many books contain charts or tables with this type of data. See our book reviews for examples. The tool for simple sugar and acidity corrections uses the input (or default) fermentation limit to predict the finished wine's sweetness (in the usual units of grams per liter). Remember that each 1 gram per liter means 0.1 percent (by weight) of residual sugar. See also the tool for measuring percentage alcohol of a finished wine which attempts a more sophisticated prediction of residual sugars.

Example 1: "Wild" grapes with high acidity and low SG We discover some wild (possibly native North American) red grape vines while camping and gather some to conduct a wine making experiment. On crushing, we discover that the grapes produce a must with a specific gravity of 1.052 and a total acidity of 12.0 grams per liter. The must volume is 37.5 liters. We plug these values into the correction tool and experiment. Because of the high acidity, we turn on the malolactic fermentation (check box) as this will help reduce acidity. We add water to reduce the acidity and sugar to increase the alcohol using the sliders. We find that if we have add about 14 liters of water and 8.2 kilograms of sugar the predicted acidity becomes about 6.5 and the potential alcohol about 12.6 percent. Uncheck the malolactic box to estimate the final acidity if malolactic fermentation does not occur. In order for malolactic fermentation to occur, the pH must be suitable, the aging temperature moderate to warm and the sulphite levels low. The sulphite tool makes predictions regarding the possibility of malolactic fermentation based on amounts of sulphite added provided that a pH reading is available. Since the grapes are red,there is probably plenty of tannin available (even with the added water) but we will add yeast nutrient in the amounts recommended on the nutrient package (or instructions). It would probably also be a good idea to add perhaps a half liter of grape concentrate. As a suggestion, add the concentrate first and then take new SG and acidity measurements. Then use the new measurements in the corrections tool. Remember, a measurement is always superior to a calculated prediction ! The advanced corrections tools permit predictions including concentrate additions.

Example 2: "Hot" California grapes with low acidity and high potential alcohol We obtain 6 "lugs" (about 98 kilograms) of very ripe red California grapes. We carefully discard any unsuitable grapes. After crushing (stems removed) we get about 67 liters of must. The SG is measured at 1.109 and the total acidity at 4.8 grams per liter. These numbers are entered into the corrections tool which predicts 15.3 percent alcohol. The yeast that we prefer could be inhibited by this high potential alcohol resulting in a stuck fermentation. Our taste preference is also for less alcohol and a more balanced wine. We will prevent malolactic fermentation with suitable sulphite additions (see the sulphite tool) so we leave the malolactic box unchecked, By experimenting with the sliders, we discover that by adding 14 liters of water and about 160 grams of tartaric acid we should get a wine with about 12.5 percent alcohol and 6.5 grams per liter total acidity. We add tartaric acid rather than acid blend as insurance against low acidity caused by an unwanted malolactic fermentation. At the alcohol level predicted, any precipitation of potassium bitartrate will not reduce the acidity below critical levels (in terms of total acidity). The tool calculates final acidity including an estimate of bitartrate precipitation. We add yeast nutrient according to the nutrient's instructions and sulphite the must at crush and when racked from gross lees etc. to prevent malolactic fermentation (see sulphite tool).

Simplified sugar adjustments (Chaptalization) to balance alcohol levels. This requires a measurement fo specific gravity (SG) using an inexpensive hydrometer. Wines with low alcohol are more unstable than properly balanced ones.

Simplified total acidity. Inexpensive acidity test kits are available. Their use is economical for even the lowest volumes of wine production. Low acidity is the most common cause of dull tasting wines and very often leads to rapid organic spoilage. If you are only willing to do one test (and adjustment), make this the one !

Tool: Basic Juice Adjustments

Purpose: Pre-fermentation additions to musts NOT containing skins.
Inputs Required: Specific gravity (SG) and total volume of the juice.
Inputs Optional: Total acidity of juice, sugar addition, water addition, acid addition (tartaric or blend toggle), malolactic toggle.
Predictions: Rough (pre-additions) wine volume and percent alcohol. Post-additions wine volume, percent alcohol, sweetness, total acidity, sugar deficit (if any) and final SG of wine assuming fermentation to dryness.

Additional Notes:

Juices are produced by crushing and pressing fruit or grapes. The pressing process separates the skins from the juice. Juices normally contains considerable amounts of pulp but no seed, skins, stems etc. Juices packaged as beverages should never be used for making wine. They normally contain additives that inhibit fermentation and seldom have enough sugar. Juices for wine production need to be almost 25 percent sugar by weight (which is too sweet for most people to drink) and are more like syrups than a beverage. If the material you are fermenting contains skins it is not a juice, it is a must. In that case, use one of the other tools suitable for fruit and grape musts.

Tannin is found in grape skins and in the skins of a few fruits like blueberries.,loganberries and blackberries. Since juices are separated from the grape or fruit skins by the pressing process, wines made from juices typically do not have significant amounts of tannin. If the wine being fermented is red, grape tannin should be added, particularly if the wine will be high in alcohol and acidity for wine stability and a balanced taste. Addition of tannin allows minimal amounts of sulphite to be added in order to provide stability. If the wine being made is white or rose, then tannin is not normally added. But in this case, to prevent spoilage and oxidation, the amount of sulphite that is added should be the correct amount for a white wine. The guidelines produced by the sulphite tool may be used. A normal nutrient addition should be made when making juice wines. For red wines from low-tannin juices typically one can add 1 teaspoon (5 [ml]) per every 5 liters of juice before fermentation. See the fruit wine design tool for more accurate amounts to add to red wines made from different types of fruit (or mixtures). Many fruits contain pectin (especially apples). Fresh pectic enzyme may be added to prevent hazes. Use the amounts recommended in the fruit wine design tool or follow the recommended amounts (see package etc.) for the enzyme you are using.

Increasing the amount of sugar in the juice will increase the juice's specific gravity (SG) and the alcoholic strength of the finished wine.

Increasing the amount of water in the juice will decrease the SG and alcoholic strength and will also decrease the total acidity of the finished wine.

If total acidity has to be reduced by the addition of water, then some added sugar may be needed to maintain a reasonable amount of alcohol. Remember that at least 10 percent alcohol by volume is required to protect the wine from spoilage organisms. And the higher the alcohol level the more stable the wine will be. Remember also that wine should contain at least 6 grams per liter (measured as tartaric acid equivalent) of total acidity to prevent a dull taste and to protect against organic spoilage. White wines are more subject to spoilage and typically have a few grams more per liter (7 or above). Another type of acidity measurement is know as "pH". This is of even more importance in preventing spoilage, but in the case of pH, low values are better. Another tool (the sulphite tool) provided for calculating reasonable amounts of sulphite. It uses the pH (if available) to determine optimal amounts of this vital addition (potassium metabisulfite) which assists yeast to compete with bacteria and molds, prevents spoilage and reduces oxidation.

Increasing the amount of tartaric acid (or acid blend) with increase the total acidity of the finished wine by the amount shown. It is assumed that the juice contains mainly tartaric and malic acid (the usual composition for grapes). For citrus or other types of fruit, it is better to use the fruit wine composition tool in order to find the amount of acid, sugar and water to add. This is because fruit other than grapes typically contain acids that are partly or entirely consumed by yeast in the fermentation. In addition, certain other vital components such as yeast nutrients and tannins are not present in most types of fruit. Fruit wines are best made by recipes based on the experience of experts encapsulated in the fruit wine design tool.

Each type of wine yeast has a particular level of alcohol which it can tolerate before it stops fermenting. Some special types of yeast can reach over 20 percent alcohol, particularly if the extra amounts of sugar required to do this are fed slowly into the secondary fermentation and other conditions such as nutrients, temperature and acidity are close to optimal. It is much more usual for yeast to stop fermenting at about 15 percent alcohol.

If sugar remains when the yeast stops fermenting, the wine will be sweet. Most producers of wine yeast make this information available. Ask where you buy your yeast if this information is not available on the package. Many books contain charts or tables with this type of data. See our book reviews for examples. The tool for simple sugar and acidity corrections uses the input (or default) fermentation limit to predict the finished wine's sweetness (in the usual units of grams per liter). Remember that each 1 gram per liter means 0.1 percent (by weight) of residual sugar. See also the tool for measuring percentage alcohol of a finished wine which attempts a more sophisticated prediction of residual sugars. The advanced corrections tools have an entry so that the user can specify the fermentation limit (percentage alcohol) at which it is anticipated the yeast will stop fermenting. If you use a proper wine yeast, the fermentation should normally proceed beyond the normal 12 or 13 percent alcohol most people prefer in a wine provided that the acidity is not too high and nutrients are available. Yeast also may quit working at higher alcohol levels if the temperature is too low. Yeast like "average" conditions and and you will reduce the chances of stuck fermentations if you let them ferment near room temperature and with moderate levels of acidity and make sure you start with enough nutrients to support a robust yeast population. Never add less than the amount of yeast recommended on the package and it does not hurt to add a bit more.

Tool: Advanced must and juice adjustments.

Purpose: More complete set of pre-fermentation additions to musts and juices with more complete specification of must properties and corrections.
Inputs Required:
Inputs Optional: Measurement temperature, ?

Additional Notes:

Temperature Adjustments. Hydrometers are calibrated to work at specific temperatures, typically roughly 15 C. Using uncorrected measurements taken at other temperatures may lead to errors and the tool will apply these corrections if the measurement temperature is entered. Brix measurements should always be made at the instrument,s calibration temperature (20C) but we recommend the use of temperature compensated instruments which are now available at reasonable prices. Once you use this instrument a few times you will not understand how you ever functioned without it !

Stems Stems (at least some) are often left in the must during the primary fermentation. They increase the must volume but not the final amount of wine produced. More important, stems introduce a great deal of tannin and other bitter substances. Powerful red wines with very high acidity and lots of alcohol are often fermented with a considerable percentage of stems left in the must. Typically, the wine produced may need to be aged five or ten years before it has "mellowed" enough to drink. If such a wine is not balanced by very high extraction of color and flavours it may never mellow ! So this type of winemaking is best left to those with the very best supply of noble grapes and the large amounts of capital required to cellar wines for several years. Some grapes may produce very high levels of tannin even with all stems removed. Certain types of grapes like tannat (used to make Madiran) have been deliberately developed with this property. Since a lot of tannin comes from the seeds, the amount of tannin in the wine may be reduced by removing the seed after two or three days of primary fermentation. Generally, the longer the seeds are exposed to the fermentation the more bitter the extraction products. This is why it is a good idea to limit the use of seed in a second fermentation (see making false wine). Unless you are able to measure tannin each day, only experience with specific grapes can guide you in the refined use of stems and seeds. Top winemakers often have a superior sense of taste and use it to detect subtle changes during fermentation. Human taste buds are sensitive to bitterness. Try tasting your wine during fermentation. If you experiment and keep accurate notes you too may become an exceptional winemaker. If you are a member of a winemaking group, you may be able to learn several times faster by tasting several fermenting musts and the resulting wines each year.

Fermentation Limits and Yeasts. Cultured wine yeast are able to survive much higher levels of alcohol than can most "wild" yeast found on grapes. They are also able to better resist the effects of sulphites making them much more compatible with modern winemaking methods. This means that cultured wine yeasts are the best insurance against "stuck fermentations". If the yeast you use cannot convert all the fermentable sugar in the must (because the alcohol level reached inhibits them), the resulting wine will be sweet rather than dry. In some wines, this is what is wanted. But in most cases this is a serious flaw and can lead to organic spoilage. Some wine yeasts can ferment to over 20 percent alcohol ! Particularly if the extra amount of sugar needed to get this much alcohol is added over several days during the secondary fermentation. If the yeast that you are using has a maximum alcohol tolerance much different from the tool's default, enter the correct value in the text area provided. Then the tool will indicate conditions when you are likely to get a sweet wine by predicting a non-zero sweetness.

Port Style Wines Certain wines are only partly fermented. The fermentation is stopped by adding a strong distilled spirit (brandy etc.). In this case, the fermentation limit is low and is determined by the winemaker not the yeast. After the fermentation is terminated, the winemaking differs from that for a typical wine and you should consult a book for details (see our book reviews). Although this method typically leaves a lot of sugar unfermented, the wine is stabilised by its high alcohol level. If you want to try making this type of wine, you need to know how much spirit to add (and when) which is what the tool does (among other things) You will also want to predict certain final properties such as sweetness and the amount of wine that will be produced. The tool can make these predictions because it permits the specification of a maximum fermentation limit and the addition of spirits. It also predicts the must SG at the point that you will need to add the spirits (that is, at the fermentation limit chosen). Note that other major issues such as acidity also need to be handled differently. Since the tool permits the addition of concentrates and water before fermentation, it is recommended that total acidity level be tested again after all additions and before the primary fermentation. Since distillation of spirits removes most of the important acids found in wines, the winemaker will probably want ot start with a must of higher than normal acidity. Then when the spirits "dilute" the wine the final acidity reached will be lower. High alcohol levels mean that the wine's organic stability is less dependant on acidity so that in this case acidity mainly an issue of taste. Generally, higher amounts of residual sugar, require more acidity for a balanced taste. Yeasts experience stress under high acidity but since the fermentation alcohol level will never be very high, many types of yeast will perform well enough to make this type of wine. In order to make good port style wine, the winemaker needs to have a sound understanding of the fermentation fundamentals and clear goals (acidity, sweetness etc.) for the final product. Why not find out the sweetness, alcohol level and acidity or your favourite style of port and see if you can make a similar product.

Tartaric Acid and Acid Blend A wine's acidity is adjusted by adding either tartaric acid or a blend of tartaric, malic and citric acids. Since malic and citric acid may be entirely consumed during fermentation (particularly in malolactic fermentation) the choice of which to add can only be made in connection with decisions about malolactic fermentation. Citric acid is cheap but since it is consumed during fermentation the reasons for adding it before fermentation are subtle (at best). Fortunately, although some acids are consumed during fermentation, other very important ones such as succinic acid are created. This acid is responsible for giving wine its main characteristic "acidity taste". In addition, acetic acid (vinegar) is produced. Vinegar is often referred to somewhat politely as "volatile acidity". A tiny bit of volatile acidity may add to a wine's complexity but amounts detectable by taste are a major flaw. This is avoided by using modern sanitation and fermentation methods. Fortunately for winemakers, the total acidity of a wine ofen does not decline very much even when certain acids are lost. This is partly because the total volume of wine produced is quite a bit less than the volume we start with (remember part of the sugar escapes as carbon dioxide, there is some evaporation etc.) so that on a grams per liter basis the final acidity tends to take care of itself. Looking at acidity from a spoilage point of view, it is the wine's pH that is critical. Because wine is "buffered solution" of salts and acids (remember any of that chemistry 101 you took?) , if we start with a suitable pH we usually also end up with a suitable low pH. One thing that wine makers sometimes worry about is the precipitation of added tartaric acid in the form of potassium bitartrate. This happens because tartaric acid is less soluble in water containing alcohol (wines). This is the reason for the old rule of thumb which specifies that not more than two grams per liter of tartaric acid should be added to a must. The precipitation of bitartrate tends to happen slowly and is encouraged by lower temperatures. This is another good reason to age wine all winter in a cool place. The tool assumes an average amounts of bitartrate will be precipitated in producing an estimate of the wine's final total acidity. Remember, measurement of properties (like acidity) produce facts while calculated predictions are an educated form of speculation ! If you really need to know, measure the acidity after fermentation. Minor acidity corrections are sometimes conducted after fermentation. Any citric acid added at this stage may stick around and even add complexity to the taste (in small amounts).

Concentrate Strength The tool permits the addition of concentrate which is generally superior to a sugar addition but is also more expensive. If you do not know the strength of the concentrate the tool suggests a way to measure it. Alternately, you can always let the tool use its default concentrate strength value and do a quick specific gravity check before fermentation. Then, if necessary, do a fine adjustment treating the new mixture as if it were just another must.

Spirits and Units Spirits strength (brandy, vodka etc.) is most reliably stated in percent alcohol by volume. If the spirits you plan to use have a strength given only in "proof" units then you will need to determine which type of proof is being used. There are at least four types of proof in use (and probably several other variants). The tool permits the strength to be input in two different types of proof. Use the percent alcohol figure whenever possible. Spirits hydrometers can be purchased fairly cheaply and these will allow you to measure proof directly and (hopefully) indicate which system they use. There are several instruments available with more than one type of scale and this may require somewhat careful use.

Tool: Alcohol Measurement

Purpose: Practical and reliable method to measure percent alcohol by volume in a finished wine.
Inputs Required: Two specific gravity measurements using a fine scale low range hydrometer.
Inputs Optional: Total acidity, temperature, glycerine addition (addition toggle and amount added text area)
Predictions: Percent alcohol by weight and estimates for total sweetness, amount of fermentable sugars remaining in wine, total amount of glycerine in wine (based on properties of a typical wine).
Tool Guide: Tool contains a detailed set of illustrated instructions for the steps required to make a measurement of percentage alcohol.

Additional Notes:

Alcoholic strength may be measured using several methods. This tool uses the most economical method we have been able to find (that produces a reliable measurement). It requires only the purchase of a low range hydrometer readable to one extra decimal of precision. These hydrometers are fairly inexpensive and using them anyone can reliably verify the amount of alcohol in a wine. If the user knows the total acidity of the wine and the temperature at which the SG measurements were taken, the tool will also make an estimate of both the fermentable and unfermentable residual sugars in the wine. Rough estimates may also be produced by assuming room temperature and the tool's default value for total acidity. To proceed, follow the four step method illustrated and described in the graphics and text areas of the tool.

Tool: Fruit Wine Composer

Purpose: Compose fruit wines following traditional guidlines.
Inputs Required: Weights of each type of fruit to add to composition.
Inputs Optional: Prefered units, substitution preferences regarding some added components.
Predictions: Volume of must and wine when reported amounts of added components such as water and acid are added to the fruit components.