What is Potassium Metabisulfite?

13 Steps to Making Red Wine from Grapes 

1. Sanitize and Crush and Destem – Inspect your grapes and remove any moldy clusters. Crush and destem into clean and sanitized food grade plastic tubs, stainless steel tanks, or glass carboys or demijohns. Always allow an extra 20% of volume for fermentation purposes as the wine will “expand” throughout fermentation. Always rinse your fermentation vessel with a sanitizing strength potassium metabisulfite solution (2oz/gallon or 3tbsp/gallon). Make sure that the sanitizing solution touches all the surfaces of the fermentation vessel and that the vessel is completely emptied out of all sanitizing solution after. Shake free any drops as best you can from the fermentation vessel. Having remaining sulfite liquid in the vessel will prohibit fermentation. Do not rinse the sanitizer off with water after sanitizing as that will reintroduce bacteria to the environment.

2. Once all of the grapes are crushed, try to accurately measure your quantity of must. Add ¼ tsp of potassium metabisulfite for every 5 gallons of must that you have. Mix up the must thoroughly.

3. Wait for 6-8 hours after the sulfite addition and then add pectic enzyme to the must. Musto Wine Grape offers generic pectic enzyme or Color Pro pectic enzyme that is specifically designed for red wine grapes. Follow the directions for the individual type of enzyme. Always mix it with water to create a 10% solution (if you use 5mls of enzyme, mix it with 45mls of water). The water allows it to better circulate throughout the must. Allow the pectic enzyme to work for 12 hours before yeast set.

4. Twenty four hours after crushing the grapes, mix the container thoroughly and take and record your measurements. Measure Brix, pH, and TA. If you need to adjust your must at all, this is the time to do it. Ideally your Brix should be between 23-28 degrees, the pH between 3.4-3.7, and the TA between 6-7g/L. Your initial Brix reading, multiplied by .55, will give you a close estimate of your ending alcohol by volume percentage.

5. If you would like to use fermentation tannins (FT Rouge, oak dust) or fermentation nutrients such as Opti-Red, add them after measurements and adjustments have been made. Musto Wine Grape packages FT Rouge and Opti Red in small packs for 5 gallon batches. If using oak dust, use 1/4cup for every 5 gallons of must. Mix any of these ingredients in thoroughly.

6. After measurements have been taken and any adjustments have been made, it is time to set yeast if you are using a cultured yeast strain. Use 1gram/gallon of wine must. Follow the yeast set directions on the packet explicitly and/or see the separate “Yeast Set” instructions.

7. After you atemperate and add your yeast, you may cover the vessel lightly with an old sheet or towel or place the lid gently on top of the bucket, if an airlock is in place. An air lock will allow the carbon dioxide to escape the pail without additional air getting in to oxidize the wine.

8. Obtain a must punch tool, a long stainless steel spoon, or your bare hands, and sanitize your tool or hands with sulfite sanitizer. This is what you will use to “punch down” or mix up the must three times a day. Try to mix everything very well, pushing all of the skins back down to the bottom, getting them very wet, and bringing up the piqued from the bottom. This should be done as often as possible, preferably three times a day. [Before work (7am), after work(5pm), and before bed (10pm)] When punching down every evening, take a sample of the liquid and using your hydrometer, track the Brix depletion. You should notice a drop in Brix daily.

9. If you are using additional yeast nutrients to assist in fermentation you will add them after fermentation has started. Fermaid O is added at the beginning of fermentation (1 day after yeast set) and all others (BSG yeast nutrient, Fermaid K, AnchorFerm) will be added at 1/3 depletion of the Brix (2/3 of the beginning amount of Brix). Follow the directions for the individual yeast nutrient, hydrating with water and mixing thoroughly.

10. If you are adding malolactic cultures to your wine, you may also chose to do this at 1/3 Brix depletion. If using a malolactic nutrient (Opti-Malo Plus) with the bacterial culture, hydrate the nutrient in a separate container from the bacteria and add to the must directly before the addition of the bacteria. Follow all directions on the bacteria and nutrient packets explicitly.

11. Punch down and take Brix measurements daily. When your hydrometer reads 0.90, you have fermented to dryness. At this point your malolactic fermentation may still continue, but the primary alcoholic fermentation is complete. You may now press the wine. Wash the press and sanitize using potassium metabisulfite. Again, make sure the press does not have an excessive puddles or lingering amounts of sanitizing solution remaining. Sanitize the receiving container (carboy, tank, demijohn, barrel) and any pumps or tubing that you may use. Anything that comes in contact with the wine should be rinsed with sulfite sanitizing solution. Place a screen or mesh (also sanitized) inside of the press to hold back any extra skins or seeds from getting through. Start scooping up the must and placing it in the press. Some of the liquid will immediately flow through, this is the “free run”. When the press is full, slowly begin pressing. Do not try and press every last drop out of the must as this can lead to seed cracking and bitterness in the wine. Fill each container to within ½” of the top and secure a bung and airlock in place. Malolactic fermentation will exude a small amount of carbon dioxide and there will be trapped gas within the wine that will need to escape the container.

12. Allow the wine to sit for 2-3 weeks. You can conduct malolactic chromatography or bring a sample to a winemaker at Musto Wine Grape for analysis to ensure that your secondary fermentation is finished. At this point you should see a nice thick layer of lees in the bottom of the carboy or demijohn. You will want to place the full vessel onto an elevated surface such as a table and place the new, sanitized, empty vessel on the floor below. Using a sanitized siphon, rack the wine into the new carboy. You may have space at the top which will need to be “topped off” with more wine. You can either use wine from another container, or finished wine to do this. It is very important that there is less than a 1/2” of headspace in each container. At this point you should also add 1/4tsp of potassium metabisulfite per 5 gallons of wine.

13. Now it is time to let your wine age. You will need to rack it and add additional SO₂ every 3 months. Make sure you sanitize all equipment and containers when racking and keep them topped off within ½”. Come visit Musto Wine Grape for bottling advice and supplies.