What’s The Skins Got To Do With It?

Grape Juice Going Into Wine GlassI  hope you can answer my question about wine to press the grapes. Why is it important to ferment the must with the grape skins prior to pressing? Your article says that white wine grapes can be pressed right away, whereas, red wine grapes is fermented prior to pressing. Please explain because I want to lean how to make white wine later this year.

Thank you,
Hello Gabriel,

This is a great question, and an area of wine making that causes some confusion for many beginning winemakers. When to press the grapes and when to have the grape pulp in the fermentation are fundamentals that need to be understood.

One thing that needs to be pointed out is that if you are making wine from concentrated juices or wine ingredient kits, the skins have nothing to do with your wine making at all. The juice producers have taken care of everything for you when it comes to handling the grape skin or pulp. So just relax.

If you take the darkest or reddest grapes you can find and run them through a grape crusher. Then press the grapes with a press. You will not have a red juice. What you will have is a pink or blush juice. If you ferment that juice you will have a pink or blush wine, not a red wine. There is nothing in the fermentation process that will make it turn more red than it was at pressing.

The color in a red wine comes from the grape skin not the juice. This is the reason that the skins are left in the must during the fermentation: so that the color can be extracted from the pulp into the juice. There are also body and aroma elements that are extracted as well making the wine more structured and complex.Buy Wine Kits

With white wines it now starts to become clear why the grapes are pressed right away. Contact with the skin has very little value when making a white wine. You are no necessarily looking for color.

Some wineries do live the pulp and skins in with the juice for a very short period of time to add depth and structure to the wine, but it is usually a matter of hours not days. For example, this might be done with a Chardonnay or Sauvignon Blanc grape where significant body is expected.

I hope this answers your question sufficiently and gives you a better idea of when to press the grapes and when to leave the pulp in with the fermentation when making your wine.

Happy Wine Making,
Customer Service at E. C. Kraus
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.

26 thoughts on “What’s The Skins Got To Do With It?

  1. Hello Herv’meister: Making beer is a very different process than making wine. You do not use pulp, but rather, grains and barley malt extract syrup. If you would like to learn more about making beer, I would suggest getting the book, "The Complete Joy Of Homebrewing".

  2. The questioned mentiond fermenting BEFORE pressing. AM I reading that right, you ferment then press?

  3. Yes, you are reading correctly. If you want a red wine you will typically press after the first few days of fermentation. With most white wines you will press before fermentation.

  4. Ed Kraus:

    I have been leaving the skins in as you point out…not because I am so darn smart…
    …but because I read everything by Ed Kraus I could get my hands on…

    EK has gotten me out of a lot of screw-ups..so his writings are my “manufacturer’s handbook”.

  5. Please expand your explanation of fermentation before pressing Red’s, my question is “ I have been buying buckets of red juice, did they fermented then press before juicing and what time do they add yeast into the bucket?”

  6. You can distillate the pulp after pressing and get some grapa. But I do not know what we can do with the rest of distillate .

    • Hello Dariush,

      Once you have made the grapa, there is little else you can do with the remainder, other than to use it as compost material for gardening.

  7. I just cut up about 10 lbs. of cherries. De-stemmed them but left the pits in. I sugar coated them and froze them. Should I cook them before putting them in my nylon bag to ferment. Or just put them in the bag with the sugar water. I just made one 6 gallon batch with 2 – 96oz cans of pre-canned harvest vin cherries. They only used about 3 lbs. cherries. I’m not sure how to get the most flavor out of my cherries. The cherries I have are very dark red & really sweet. I plan to follow those instruction. that calls for 14 lbs of sugar per 6 gallons. The canned cherry batch is now in the 2nd ferment carboy with a high alcohol content. Is 10lbs. of cherries to much for one batch?? And do I need to cook them???

    • Fred, when making wine from almost all fresh fruit, you do not want to extract the juice first by cooking or any other method, but rather you want to put the fruit in the primary fermentation, itself. The fermentation activity is what extracts the juice and flavor from the fruit. It does it for you. Below I have also included the link for our 5-gallon Cherry Wine Recipe. Our recipe calls for 20 pounds for 5-gallons. You can use this recipe and adjust it to make 6-gallons.

      Cherry Wine Recipe

  8. Beginner wine maker here with a number of questions on the 7 easy steps that sound easy but the devil is always in the details and the article on when to press is quite the devil.
    First question, Step 1 calls for busting skins on smaller fruits. I will be making blueberry ine in another month and I was planning on placing the blueberries into a fruit press, but it sounds like I should not be do that. What would be you suggestion as the easiest way to bust the skins on a blueberry.
    Second question, Step 2 calls for stirring together all ingredients except yeast but then it states to collect pulp and place into a fermentation bag. The illustration shows adding the fruit with all the other ingredients. So do I stir in all the fruit with all the other ingredients then use a strainer or some other utensil to extract the pulp from the mixture and place in the bag which is then submerged back into the mixture?
    Third question, Step 5 after 5-7 days of fermentation remove the pulp and discard. So when am I supposed to press the fruit?

    • Hello Barry, let me see if we can clear this up for you. Before you can press juice from the berries, they do need to be crushed. When dealing with small amounts of fruit, you can simply crush them by hand with something as simple as a potato masher for example. When dealing with larger quantities, you can put the fruit in a bucket and crush it with the sanitized end of a 2X4. If dealing with even larger amounts, a fruit crusher would be the way to go.

      As far as adding the ingredients, when the directions state to collect the pulp it means to collect it from whatever you crushed it in and place it in a fermentation bag. The fruit does not need to be floating freely in the must while adding the ingredients.

      On step 5, you will remove the bag, squeeze the bag to press out the juice or you can place the fruit in your press to extract the remaining juice.

  9. Thanks for the info about what the grape skins are used for. What I was wondering is after they are used in the fermenting process are they used for any other purpose? If nothing for modern days, was there any use in more ancient days. Thanks

  10. Larry, I do not know of any specific information on this. I do know that some wineries do throw the pulp under the vines for nutrients. And I have heard of larger wineries selling/donating the pulp for feed.

  11. question on concord grapes, I live in PA where the acid level in grapes is high. Do we need to add the acid blend? Also, at a wine festival, I sampled a concord/blackberry wine. The blackberry was at a lower level than the concord. Do you happen to have a recipe for this?

    • Patty, the only way to know if you need to add acid is by taking an acid reading. Below you will find the link to our Blackberry recipe. We have no way of knowing if it is similar to what you sampled. Most fruit wines have a acid reading of .55 to .65 percent.

      Blackberry Wine

  12. Ed,
    Would there be a problem with flavors if I was to ferment a white wine on the skins? I did ferment some Delaware on the skins once which turned the juice into a pink wine and the flavors weren’t that good. So I blended some Norton to it to darken it up and that also helped with the flavor of the finished product.

    • Jim, Contact with the skin has very little value when making a white wine. However, some wineries do leave the pulp and skins in with the juice for a very short period of time to add depth and structure to the wine, but it is usually a matter of hours not days. For example, this might be done with a Chardonnay or Sauvignon Blanc grape where significant body is expected.

  13. On the question about cherry wine, Is it OK to ferment with the pits or do they need to be removed?

    • Jill, The cherry pits do need to be removed. They can cause the wine to become too bitter. Cherry pits can also contain harmful substances.

  14. Hi! I wanted your opinion about making sour cherry wine – I have your recipe for cherry wine (5 gals). But in my purchase of the cherries only came in 30 lb containers. Can I make the wine into 5 or 6 gals with the 30 lbs or should I increase the water to about 8 gals? If I need to increase the ingredients can you send me the adjustments for 30lbs of cherries? Thanks so much! Gary

    • Gary, Our Cherry wine recipe calls for 20 pounds of cherries. If you have 30 pounds, using our recipe you can make about 7.5 gallons of wine. All you need to do is divide all of the ingredients by 5 to turn it into a one-gallon recipe, then you can multiply that number by the number of gallons you want to make.

  15. Hello-
    I pressed my Syrah grapes when the SG was 1.010 and transferred the juice into carboys. Will the juice continue to ferment to dry and can I also inoculate the juice with malolactic bacteria while the primary fermentation completes?
    Thanks, Bob

    • Bob, Yes, the wine will continue to ferment until it completes. The time to add the malolactic culture is after the fermentation completes. You do not want to add the sulfites until after the malolactic is complete because the sufites may prohibit any activity,

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