Stir It Up
These are signs that the wine was not sufficiently degassed before bottling, and while the wine is drinkable, it can be annoying.
Master Vintner kits are designed to be ready to bottle in six weeks or less, while commercial wines are often left for a year (or more!) before they're bottled. We manage this by careful formulation and blending, excellent yeast and nutrient choices, and juices that require only gentle fining agents to clear quickly and completely.
The one thing we can't fully compensate for is CO2 saturation. When the yeast consumes sugars and produces alcohol, it also produces a lot of carbon dioxide--dozens of cubic feet in all. Because the wine only sits for four to six weeks it doesn't have the chance to expel all of the carbon dioxide created during fermentation.
The solution is to work it out of the wine yourself. The instructions tell you
CO2 nucleation is what happens when a fizzy wine has a particle in it. CO2 is reluctant to come out of solution. If you've ever left a can of soda pop on the counter overnight, it isn't as fizzy as the moment you opened it, but it still has a lot of bubbles. But if you pour a spoonful of salt (or sugar or sand, anything will do) into that soda, it will foam up like crazy--remember the Mentos and Coke videos a few years ago? Those went crazy because Mentos candy is made from crystal sugar that's compacted into a little pellet. Throw one in soda and boom! All of the gas gushes out.
It's less dramatic in your Master Vintner kit, but the particles of yeast, protein and fining agents will cause gas to come out of suspension slowly and evenly. These particles, now surrounded by a bubble will float up to the top of the wine, dragging all the goo off of the bottom, preventing clearing.
Even if your wine does clear, it will be fizzy and could harbour fermentation aromas, nearly all of which are related to thiols, which have a deep whiff of sulfur (eww).
You can make the stirring process more effective by using three strategies. First, warmer liquid releases gas more readily (think of a warm soda pop can versus a cold one), so if you have the wine closer to the top of the specified temperature range of 65-75F the carbon dioxide will come out a lot more easily.
Secondly, if you can degas on a rainy or overcast day, the lower barometric pressure will also allow the gas to come out more easily.
Third, a Wine Whip or other drill-mounted stirring implement will do an incredible job of degassing. That's because the tip of the whip acts just like a supercharged particle in the wine, causing both gas nucleation and something called Tip Vortex Cavitation. No need to go into it, but it's like a sonic boom for wine, really going to town on those bubbles.
You really can't lessen the need for some mad stirring of your wine however you do it. Keep your eye on the prize, grit your teeth, and set a timer to make sure you do all the stirring you need to. When it's all over, you can be content knowing that a rich, delicious prize that awaits you in just a few more weeks..