After the primary fermentation has slowed down (after about 7 days) it’s time to check the specific gravity. What this tells us is how the density of the wine compares to that of water.

Grape juice is more dense than water. Thus before we fermented the grape juice the specific gravity was over 1.0. As the yeast converted the sugar into alcohol and carbon dioxide during fermentation, the density of the wine has been decreasing. A specific gravity less than 0.990 tells us that the primary fermentation has slowed down enough that we need to rack.

Our main concern is leaving the wine on the dead yeast, or lees, for too long. Wine is sometimes left on the decomposing yeast to impart a nutty flavor, however, you really need to know how to time this right. Left too long and the wine will start to taste like rotting yeast.

Check out this video to see all the steps involved in this part of the wine making process.¬†The racking cane can be a bit tricky to get going so I’ve created a separate video all about¬†how to use a racking cane. Hint, you don’t want to use your mouth to get this going!

If you found this video helpful please leave your thoughts in the comments below.

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  • CalgaryWinegirl

    Great video….thanks! One comment…it would have been great to see exactly how you did the syphon with the water in it. I ended up going to youtube for a quick lesson. Also maybe mention when wine is NOT ready to rack….maybe I missed that but what numbers don’t you want to see?

    • Thanks! I created another video that shows my exact process for filling a racking cane and tube with water here: http://winemakersacademy.com/racking-cane/

      I’ll go ahead and add a link to this post, thank you for mentioning that.

      As for the specific gravity readings you’re looking for, that can vary a little bit but most kits have you rack at or below 1.010.

      I’ve got an article due out very soon that will be covering when you should rack. Thank you for all your great questions. Cheers!

  • W.Beeman

    So am I understanding correctly from what you say that you should not rack until the S.G. is below 1.010? Same case for my mead at .998. Should I rack?

    • I would rack between 1.020 and 1.010. Going much below 1.010 can put more fragile yeast strains in shock which may result in a stuck fermentation.

      Mead can be a bit tricky because it ferments forever. I’ve racked both wines and meads at around 1.000 and not had trouble. That could be because of the strong yeast strains I’ve tended toward or just luck.

      If you need to get off the lees to prevent off flavors and aromas go ahead rack, but rack carefully and slowly. A good rule of thumb though is to rack between 1.020 and 1.010.

      Cheers! -Matt