In ancient Greece, it was custom for a dinner host to take the first sip of wine to assure that the wine served to guests was not poisoned. The tradition of “toasting” started in ancient Rome when the Romans continued the Greek custom of “drinking to one’s health and well-being.” They dropped a piece of toasted bread into each wine glass to temper undesirable tastes or excessive acidity of the often-bitter wine. Today, we celebrate honor and signify meaningful events with toasts and clinking of wine glasses. ISO 5704:1980—Equipment For Vine Cultivation And Wine Making – Grape-Harvesting Machinery – Test Methods provides test methods for machines used in grape-harvesting for vine cultivation and wine making.
What Is ISO 5704?
ISO 5704:1980 specifies technical test methods for machines designed for carrying out all operation involved in grape-harvesting. It applies in cases where the grapes are used for wine making or making other beverages (grape-juice, spirit-of-wine, etc.). Tests for grape-harvesting machinery are designed to:
- Assess the performance of the quality of grapes and beverages, exfoliation of grape-vines, damage to vine-stock (likely to affect subsequent pruning), “visible” losses on grape-vine or ground, and loss of juice of crushed grapes
- Record the performance in terms of operating times
- Observe the mechanical operation, reliability, and performance of varying ground and any possible effects on stake and wire arrangements
What Is the Most Planted Fruit Crop in the World?—Grapes
Grapes are the most planted fruit all over the world with more than 29,000 square miles (about 75,000 square km) of space being used and about 150 trillion pounds (68 trillion kg) of grapes being produced annually. The prevalence of grape crops is mainly thought to be because of their adaptability to most climates. The majority of grapes (about 70%) are used to make wine, and there are 10,000 varieties of wine grapes existing worldwide.
How Is Wine Made?
Harvest decisions, fermentation choices, vinification methods, aging regimens, and bottling options all play major roles in the lengthy process of making wine and importantly how a wine ends up tasting.
Getting fruit from the vineyard to the winery is the first step in the winemaking process. Choosing the ideal picking date is critical—the grape should have the right acidity and sugar levels. When the time is deemed right, teams are gathered and sent out into the vines to collect the fruit. Harvesting can be done one either by hand or by machine. By hand takes longer, but it allows for more quality control and sorting in the vineyard. By machine is generally done at larger estates that have more ground to cover. ISO 5704:1980 applies to mechanical harvesting in which the required samples of harvested grapes and grape-vines are examined for quality (e.g., examining if any complete or broken grape-less stalks remaining on vines after the machine has passed) in comparison to those obtained from a manual harvest.
2. Crushing and Pressing Grapes
Depending on whether white, rosé, orange, or red wines are being made, the way grapes are crushed or pressed varies. For white wines, fruit is generally crushed and pressed, meaning that juice is quickly removed from contact with the grape skins. Once pressed, the juice is then moved into a tank to settle, then racked off of the sediment. For rosé, the harvested grapes are red, and just after being picked, they are gently pressed. The juice that comes out, percolating, extracts a bit of color from the skins which instead remains trapped in the grids of the press: the juice will then be pink. For orange and red wines, the fruit is crushed (with or without stems) and left on the skins for a given period of time to macerate. This is what ultimately gives red and orange wines their color and tannin structure.
Fermentation (adding yeast and sugar to create alcohol and carbon dioxide) in winemaking is what converts grapes into alcohol. Fermentations can be done with either native yeasts or cultivated yeasts. Native yeast fermentations (or spontaneous fermentations) are executed with naturally present yeasts found on grape skins and in a winery’s environment. Cultivated yeast fermentations are implemented by using purchased strains of yeast and adding them to the juice to execute the process. Spontaneous fermentations tend to take much longer and are often credited with producing more complex final wines. Moreover, during this vinification process, ISO 5704:1980 specifies to carry out all oenological tests such as free acidity, tannin content, dry extract, metal content, color, oxygen reduction capacity, etc.
Most winemakers will choose to age their wines in steel, cement, or oak, although terra cotta or clay, glass and other vessels are also possible options. Aging wine in steel creates a nonoxidative environment, meaning that wines are not exposed to oxygen. This tends to preserve fresh fruit-driven flavors in the wine, and no external tannins or flavor are added from wood. On the other hand, oak aging creates an oxidative environment, meaning that the wine has contact with oxygen. This enables the wine to develop different levels of texture and flavors. When new oak (as opposed to neutral or used wood) is used, flavors of vanilla, baking spice, coconut and/or dill can often be tasted in the resulting wine.
Once the wines are aged and fined and/or filtered, the wine is finally bottled and ready to get packaged. Some winemakers may choose to additionally age their wines in the bottle prior to releasing them on the market. Once bottled, the wines are labeled and sealed (with corks, screw caps or other closures) and are sent off to be delivered.
To learn more about the standardization of wine-making processes and equipment, check out other ISO Wine Making Standards.
ISO 5704:1980—Equipment For Vine Cultivation And Wine Making – Grape-Harvesting Machinery – Test Methods is available on the ANSI Webstore.