sábado, 14 de febrero de 2009


Level IV: Clarification

Solid particles in wine fermentation could be from 3 types: Fruit fibres, Yeast and proteins based particles. After fermentation you should filtrer organic solids (Fruit fibres and proteins based particles) by using a fabric or similar devices. Vaccum could be used too but sometimes it results expensive. The most economic alternative is sedimentation or flotation techniques, depending of solid density.

Yeast is particularly small and it soul be separed from fermented wine by sedimentation and decantation.

During clarification process avoid the contact of wine with air, remember oxygen oxides the wine compounds and provides optimal condition for bacterial degradation.

lunes, 9 de febrero de 2009


Level II: Must preparation

The fruits are harvested both by hand and with motorized harvesters. However, harvesting by hand is more recommended. Avoid an exposure to air and temperatures up to 27 ºC.

A plastic material is recommended for fruit handle. Fermentation vessel should be made of plastic or glass too.

After harvest, fill the fermentation vessel with approximately 1/3 of fruit and complete the total volume with water and others additives such as sugar and organic acids for pH adjust.

Sugar concentration before fermentation should be 200 g per liter of must, however it is a free variable defined by the winemaker. A white sugar must be used for all winemade production. Remember: final colour is the key for a good selling and wine acceptance.

Some authors recommend the use of sulphites for oxygen control during anaerobic fermentation; however my experience in this field shows that sulphites could promote the wine degradation by the formation of sulphur compounds. So do not use them.

Yeast is rehydrated under warm water (28ºC) for 1 hour, prepare a stock solution of 1g yeast per liter and add a 10% of total must volume to the fermentation. For example if the most volume is 2000 mL a 200 mL of yeast solution is required.

Once you add the yeast solution to the must the fermentation has started.

Level III. The heavy machine … The Fermenter

Fermenter design has vital importance for winemaking process. All the fruit transformation occurs here and the success of final product is obtained here. Fermenter is practically a closed vessel, at the top is inserted a rubber pipe for gas exhaust (CO2), remember, in order to make your process safely is obligatory to control the vessel pressure. Really a fermenter is simple to design and build, plastic and glass materials are recommended.

Fermenter fill volume is normally 80% of total capacity.

It could be washed by using a diluted NaOH solution

domingo, 1 de febrero de 2009


Level I: Raw Materials Required

1) The most important: The grapes or other Fruits

Fruits carry the most vital part. It requires an adequate equilibrium of sugars, organic acids, water content and in some cases tannins. The quality of wine depends very much on the quality of fruits that are going to be used.

The ripe grapes contain a solution of water and sugar and the skins contain nature yeasts, however the experience shows that it is necessary to utilise Saccharomyces cerevisiae yeast due to its ability to produce ethanol from sugar and resist low pH under anaerobic conditions. On next we will explain more about this yeast.

Wine grapes contain various exclusive signature characteristics. These varieties can change the quality of a wine. Some popular and frequently used grapes are:

- Red Grapes:

Cabernet Sauvignon, Pinot Noir, Merlot, Sangiovese, Syrah (Shiraz), Zinfandel and Tempranillo.

- White Grapes:

Chardonnay (Recommended for Champagne production), Gruner Veltliner, Gewurztraminer, Pinot Blanc, Riesling, Semillon and Sauvignon Blanc.

- Fruits:

Almost all fruits could be used in wine making; however I recommend these fruits to produce wine: strawberries, bananas (Final color is gold, like a beer), apples, pineapples, tangerines, kiwi, orange, pear, Cape gooseberry.

I employed too multiple exotic fruits of South America such as: Borojó (Some people says it is aphrodisiac), Corozo (member of coconut family) and other strange fruit that I will tell you soon.

2) Sugar & Yeast

In the past people used to let the nature yeast to ferment among the fruits extract (known as “must”), and it became the wine process slow and ineffective for ethanol production. Additionally risk of methanol production due to its metabolism was higher.

The most important thing to learn about how to make wine is the importance of sugar and yeast to your wines. White sugar is usually always used for producing fine wine and all the sugar should be dissolved before including anything. Verify the homogeneity of “must” before fermentation.

The yeast used by bakers, known as Saccharomyces cerevisiae is another important ingredient for making wine during this stage. You can purchase yeast from your local bakery or wine supply store. Normally yeast in the market are lyophilized, so you must to rehydrate them in the presence of sugar before add them to the fermentation, you can dissolve the properly yeast in a 250 mL bowl with water and 5g of sugar for 1 hour at 30ºC. Normally the yeast required for fermentation is estimated as: 1 g dry yeast per liter of must before fermentation.

Yeast should not be added too early. If it is added below the boiling point, the yeast organism will be destroyed and no fermentation will take place.

3) Citric or tartaric acid for pH control

It is desirable that pH value of must before fermentation was approximately 4.0 or below. However many non citric fruits such as strawberries or apples reach a pH value higher than 4.0, so it is important to control pH to avoid principally bacterial fermentation or in other words the production of undesirable “Acetic acid”

For pH control you can use solutions of either citric or tartaric acid solutions, by adding continuously drops to the must and verifying pH adjust.