Winemaking 101 Pt. 2 - Crush and Primary Fermentation
Earlier this year, I collected and froze 15 lbs. of red raspberries. Now join me as I start the process of turning them into 5 gallons of wine.
The first stage of winemaking is initiating primary fermentation. Your fruit is crushed and/or the juice is pressed out and put into the primary fermenter. (For information on equipment and terms see these previous posts) Water and sugar, if necessary, are mixed in along with a number of additives to create the must. For the raspberry wine I’ll be using the following additives.
Nutrient powder – This contains trace elements necessary for yeast to grow and multiply. Many grapes naturally have all of these elements, but many fruit and berry wines need the addition of the nutrient powder to insure happy yeast.
Acid Blend powder – Many fruits don’t contain sufficient natural acids to create a balanced wine. This powder contains a mixture of citric, malic and tartaric acid to increase the acidity of the must.
Pectic Enzyme powder – Pectic enzymes weaken the cell walls in fruits to help release flavor and color into the must. They also break down natural fruit pectins that can cause cloudiness in wines.
Super Energizer – This is an additional yeast nutrient that includes vitamins to aid in rapid yeast growth.
Campden tablets – These are premeasured doses of sodium or potassium metabisulfite that are used to inhibit wild yeasts, bacteria, molds, and other unwanted organisms in the must. Use 1 tablet per gallon. When you see “Contains sulfites” on the label of a wine bottle, this is the substance they are referring to.
These additives are inexpensive and readily available at any winemaking/brewing shop or online. Now let’s put these together with the fruit, water, sugar and yeast and get this wine started.
Raspberries in the food mill
After thawing the raspberries thoroughly, it’s time to crush them and put them in the primary fermenter. I use 3 lbs of fruit per gallon of finished raspberry wine. The primary and any equipment that comes in contact with your wine must be cleaned thoroughly, and then sterilized with a rinse of sanitizer (I use a sulfite solution). It is crucial that your equipment be as clean and sanitary as possible to prevent unwanted organisms from contaminating your wine and altering the flavors and aromas. I crush the fruit in a food mill with the tension set loosely so that the seeds are not damaged as breaking the seed coats can release unwanted flavors. All juice and pulp are added to the fermenter along with the water, sugar, and other additives as listed below. Here’s the basic recipe for a 5 gallon batch.
15 lbs. raspberries
5 ½ gallons water
2T Nutrient powder
4t Acid Blend powder
3t Pectic Enzyme powder
1 ½ t Super Energizer
6 Campden tablets
After the crushed fruit is in the primary, I add the water, mix thoroughly and draw a sample to measure the level of natural sugar in the must. The sample is strained to remove solids and enough poured into a measuring tube to float a hydrometer, which is used to determine how much sugar is present. The hydrometer is placed into the tube and spun to release any air bubbles. Sight across the top of the liquid level to read the scale. The higher the hydrometer sits in the must, the more sugar is present. I use the Specific Gravity scale to determine how much sugar I need to add. Hydrometers also commonly have Brix or Balling, and Potential Alcohol scales as well.
Hydrometer in measuring tube
The initial s.g. reading of my must was 1.005. If this sugar ferments out completely it would result in a wine with only about 1% alcohol, sadly lacking. In order to have a finished wine with my target of 12% alcohol I needed to add enough sugar to the must to bring the specific gravity reading up to 1.090. 2 oz. of sugar added to one gallon of must will raise the s.g. by 0.005. 15 ½ lbs of sugar mixed completely into the must gave me the reading I wanted. This was somewhat more than the calculations may have indicated, but the volume of fruit and juice changes the total amount of must, and the addition of sugar also increases the volume. Make your calculations, add the sugar, measure, and adjust until you are where you want to be. Advanced winemakers will also test pH and acid levels at this point. Be sure to taste your must as you go to familiarize yourself with the changing flavors.
After the sugar level was established, I crushed the Campden tablets in a mortar and pestle, added the remaining dry ingredients, and dissolved the additives in a cup of warm water. This then went into the primary and everything was well mixed. The lid was placed on the fermenter and it was set aside to wait 24 hours at room temperature for the campden tablets to work prior to adding the yeast.
The next day I opened a package of Red Star Premier Cuvee winemaking yeast, my preferred yeast for berry wines, and dissolved it in about 1/3 cup of warm water, stirring well. I then poured it gently on the top of the must. By the following day you could see the yeast starting to work and a cap of fruit solids and yeast starting to form. Soon fermentation will be vigorously active and you'll actually hear it "sizzle". The must will be stirred and the cap punched down (mixed into the must) twice daily for the next 4-7 days, until the sugar ferments out to a s.g. reading of 1.040. Then it’s time for the first racking into the secondary fermenter.
The yeast is starting to work and form the cap. Always leave some head space in your primary as the active fermentation will raise the level of the cap. You'll have a mess if you don't!