Craft & Cork >> Winemaking

January 21, 2016 | By RJS Craft Winemaking

The inside scoop on grape skins

If you’ve ever peeled a red grape, you’ll have seen something interesting: the flesh is actually pale yellow–not red– and if you eat it separately from the skin it’s sweet, but actually kind of bland. That’s because all of the colour and tannin, and most of their flavour and aroma are stored in the skin (and the seeds) of the grape. If you press red grapes immediately after crushing, you get pale yellow juice. To make red wine you have to macerate (soak) the skins and the flesh together in order to get all of that colour/tannin/flavour/aroma in to the juice.

Man holding dried grape skins
Dried Grape Skins

All wine kits are made from grapes (you can’t make them out of anything else!) and just like commercial red wine, the grapes are crushed and macerated, pressed, clarified, carefully balanced and blended, then packaged into that sturdy box that you pour neatly into your fermenter. With a few additions and a bit of stirring you’re on the path to bottling day.

 

 

Colour and Tannin

Despite our winemakers’ efforts to get the maximum extraction into wine kits, it’s difficult to get out 100% of the compounds from the skins and seeds. Some of the tannins, flavours and colours, including some desirable ones, are best extracted with an alcohol solution–like in regular commercial winemaking. That’s where GenuWine Winery Grape Skin packs come in. Adding GenuWine Winery Grape Skins to the must allows the alcohol fermentation to go that extra mile to get the good stuff out of the grapes and into your own craft wine.

GWlogoThe Packs

There are two main sorts of GenuWine Winery Grape Skins, dried and crushed.  Each provides colour and tannin to the must for improved alcohol extraction.  Both types of grape skin packs are processed to maximize the extractability of the material, and they break down to a point where even five or six days of fermentation will extract all of their goodness.

The GenuWine Winery Dried Grape Skins supply a high volume of skin and seed material for a given weight/volume of pack, while the GenuWine Winery Crushed Grape Skin packs use heavily processed skins suspended in heavy juice, looking a lot like jam.

Man holding crushed grape skins
Crushed Grape Skins

Each approach has its merits:  typically a finished 23 litre (5 gallon) batch of wine will take about 45 kilos (100 pounds) of grapes. If you’re trying to boost the alcohol-soluble tannins and colour in your finished wine you’ll want to maximise the amount of grape skin material. Dried skins do that by removing all of the extra water, and most of the stems and cellulose for a compact, tidy package.

Crushed grape packs typically come in a size that’s roughly 10-15% % of the total volume of the kit, packed in very high sugar solution of grape juice concentrate. Because crushed packs contain more pulp, cellulose and goo, they typically contain only a little more grapes than the dried packs, but they pack an even bigger punch.

The Finished Product

Whichever grape pack you choose, it will help you make a bigger, bolder wine that drinks well young in addition to aging to smooth perfection, adding smooth tannins, robust colour and rich aromas—GenuWine Winery Grape Skins really are the perfect addition to a great wine.

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26 thoughts on “The inside scoop on grape skins”

    1. Hi Irmina,

      You do not need to soak the dried grape skins before adding them., you can add them directly into the muslin bag.
      Happy winemaking!

    1. Hi Nik,

      We do not sell our GenuWine Winery Grape Skins individually but you can find them in our select Cru International, Cru Select, or En Primeur Winery Series wine kits.

    1. Hello,

      If your kit came with the Genuwine Wet Grape skins you should remove them on day 7 of fermentation or when the specific gravity has reached 1.020 or below. If your kit came with Genuwine Dried Grape skins you can keep them in for 14 days or when the specific gravity reaches 0.998 or below.

      Hope that helps.

      – RJS

  1. My wine has been slow to get going. I have re entered the yeast packet and now everything is going well. With the time with no fermentation, the wine skins sat in the must for an extra week. I plan to let everything continue until the primary fermentation completes. Is there anything else I should do, or should I remove the grape skins earlier?

    1. Hi Ralph,

      If your kit included wet grape skins I recommend removing them when the specific gravity has reached 1.020 or below or around day 7. You will then add the pectinase to the wine and stir it up thoroughly. If your kit came with dry grape skins you can leave them in the wine until the specific gravity reaches 0.998 or below which should be around day 14. Day 1 of your fermentation would have been the day that the second packet of yeast was added to the juice.

      Let us know how it all turns out! 🙂

  2. I purchased a Craft Barbera that came with a wet skin pack and a sock. Directions say to use the sock, which I did. I stirred it, but the skin sock is still very clumply. and sinks to the bottom. What is the downside, if any, of just stirring the skins into the jiuce without the sock? I guess that would reqiure a straining upon racking to secondary fermenter, right? I’m at hour 24 of pitching and firmentation is getting visible. Once the yeast gets highly active, will it start “churning” the skin-sock anyway, so that in the end the sock works just as well as free-floating skins in the must?

    1. Hi Charles,

      Using the white straining bag to hold the wet grape skins is definitely the easiest way to add and remove the skins to the wine. The fact that the straining bag has sank to the bottom of the fermenter is a good thing. This will help with flavor and tannin and extraction by keeping the skins in contact with the juice. Choosing to add the grape skins directly to the juice is a good way of getting even more extraction from the skins. It will require extra work when racking into the carboy after the primary fermentation but will result in a wine with more tannin, flavor, and color.

      Hope that helps. Let us know how it turns out!

  3. I have been making excellent wines with the winery series kits for a few years.
    About a year ago I noticed the addition of pectinase before secondary fermentation.
    I assumed that this was an improvement in the process to achieve better color and flavor extraction.
    If so why is it not added while the skins are still in the must?
    When I started using the winery series a few years ago i noticed some of my wines dropped a clumpy sediment in the bottles after a year or so, no detriment to the wine but means that I have to decant before serving. Also I don’t like to gift these wines without rebottling. (Pain in the a…)
    I have been leaving these wines in a carbon for bulk aging ( a few months) to try to avoid the sediment in my finished bottles.
    I assumed that the pectinase would help in quicker, better clearing. It does help but still get some sediment in the bottles after several months of storage.
    I ferment at 75 deg.F. Must temp. Secondary temp is lowered to 70. Clarifying bulk aging and bottle storage is at 56 deg.F. ( cellar temp.) bottles stored on their side.
    Why are some recent winery series kits supplied with pectinase ( white instruction sheet ) and some not ( red instruction sheet.) am I getting some old stock. How do I tell production date from product code date.

    Any advice would be appreciated.
    We all enjoy the wines made from these kits, my friends who know wines tell me they compare to commercial wines costing $ 20-30 +

  4. I am growing Cabernet grapes but do not have enough to make wine. Can I add my grapes to a Cabernet kit. If I did would I do everything else the same.

    1. Hi Kenny

      Thanks for your inquiry. Yes, you absolutely can use the Cabernet grapes from your vineyard in one of our Cabernet kits. Make sure that you remove the rachis (stems) from the grapes first as you don’t want to produce a wine that is too astringent. It is also best to try and crush the grapes a little bit first as this will help in the extraction of flavor and color from your grapes. Make sure to take a specific gravity measurement once you have added the grapes to the juice. Ensure that your starting S.G is no higher than 1.110. Once you have done this, you are ready to start making your wine!

      Happy winemaking!

  5. Hi Kenny

    Thanks for your inquiry. Yes, you absolutely can use the Cabernet grapes from your vineyard in one of our Cabernet kits. Make sure that you remove the rachis (stems) from the grapes first as you don’t want to produce a wine that is too astringent. It is also best to try and crush the grapes a little bit first as this will help in the extraction of flavor and color from your grapes. Make sure to take a specific gravity measurement once you have added the grapes to the juice. Ensure that your starting S.G is no higher than 1.110. Once you have done this, you are ready to start making your wine!

    Happy winemaking!

  6. Hi Harry,

    Thank you very much for your inquiry, we are very pleased to hear that you have been enjoying our wine kits!
    You are correct, pectinase is typically added early on in the winemaking process to aid in color and flavor extraction from skins. Another important role of pectinase is the breakdown of pectin that is released into the wine from the skins and can cause clarification and filtration issues. By adding the pectinase with the grape skins removed from the wine, the pectinase will be able to work more efficiently by acting on just the pectin that has already been extracted naturally by the fermentation.

    Bulk ageing these wines will definitely help to settle out most of the colloidal proteins and pectin molecules that can cause sediment in bottle, however it will not remove everything. The best way to prevent the formation of sediment in bottle after a year or more of ageing is to filter your wine using #2 (2.5 micron) filter pads. If you do not have a filter you can always ask your local U-Brew retailer if they can filter the wine for you or you can possibly rent the filter from them.

    The temperatures that you are fermenting, bulk ageing, and cellaring at are perfect, so don’t change anything there! Our Winery Series kits have been using pectinase for about the last 2 years so if you have a Winery Series kit that contains wet grape skins it should have a package of pectinase. The date code (YYYYMMDD) information found on the white peel off sticker on top of the box indicates the day the kit was produced.

    I hope this answers your question! If you need additional clarification you can always email us at rjsinfo@cbrands.com or call us at 1 800 663 0954.

  7. Hi there,
    I bought the Cru select malbec kit. It comes with the grape skins and the oak chips. This is my first time brewing and I have the fast ferment.
    I have one nylon mesh bag to hang from the lid of the fast ferment. Do I rip open the oak chips bag and put it directly into the mesh bag? How about the grape skins bag (it looks like the skins are inside a teabag type)? Can I put everything into the one mesh bag?

    Thank you,

    1. Hello Alex,

      Our Cru Select Chile Style Malbec kit does not come with grape skins. This kit should come with 1 heavy toast French oak tea-bag which you can add directly to the juice without opening the tea bag. This kit should also come with 1 (50g) package of Hungarian oak shavings which you can also add directly to the juice before you add the yeast. If you have a mesh bag then you can also add the oak shavings to this bag which will help with the removal of the oak after the fermentation.

      Thanks!

  8. I really enjoyed reading the questions and answers. I make wine out of Black Spanish grapes, and would like to darken the color, the maceration time is about 72 hours, should I let it set longer, and use the Pectinase, and where can buy Pectinase.

    Steve

    1. Thank you for your inquiry. There are a number of things that you can do to extract more color out of the skins during the maceration.

      1. Once you have crushed your grapes and you have them in your fermenter, drain off 2 liters (0.5 US GAL) of juice per 23L (6 US GAL) of crushed grapes from your fermenter. This will increase the skin to juice ratio resulting in more color extraction. The 2L of juice that is drained off can be fermented separately to make a rose.
      2. Pectinase, if added to your crushed grapes will also help release more color in your juice during maceration. Adding 2 TSP of pectinase per 23L (6 US GAL) of crushed grapes will help extract more color. Make sure that this pectinase is added to 100mL of water at 20°C (68°F) and is dissolved before adding to your grapes. You can purchase pectinase at your local grocery store. You can also purchase pectin enzymes specially designed for extracting color from the skins on many online winemaking retail websites.

      Don’t hesitate contacting us for more information at 1800 663 0954 or rjsinfo@cbrands.com

  9. Hello!
    I can’t complete my order in your store!
    Why don’t you setup more stable processing like paypal.com or paymenthub.online?
    PayPal.com charges 3%, Paymenthub.online just 0.1% and setup is free.

  10. Hello!
    I can’t complete my order in your store!
    Why don’t you setup more stable processing like paypal.com or paymenthub.online?
    PayPal.com charges 3%, Paymenthub.online just 0.1% and setup is free.

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