It seems to me like your Carmenère is a candidate for one of the “Wine Wizard’s” cheapest, easiest and most favorite ways to improve a tannic wine; egg white fining! What could be simpler (or more traditional) than grabbing an egg or two from the fridge. Egg whites are mostly made up of a pure protein called albumen, which has been used by winemakers for centuries to clarify, settle and lessen the tannin content in their wines. Depending on how much you add, the egg whites will cling to an increasingly large amount of the bitter and tannic elements in your wine and, as the protein molecules stick together and get bigger, they will eventually become so heavy as to fall to the bottom of your carboy, barrel or tank, effectively forming a layer of sediment at the bottom off of which you can rack the cleaned-up and less-tannic wine.
Sometimes wines just need a little bit of added egg white to get the desired effect, say like a Pinot Noir. Heavier reds tend to need a heavier hand, and Carmenère can sometimes be a beast. I’ve had lighter-style Carmenères but it sounds like you’ve got one with significant tannin. Since I don’t know how large your kit size is (the Cellar Craft website says they range from 7.5-16 L) and can’t taste your wine, all I can give you is an approximate range of addition. As a reader of my column, you know I’m a proponent of people doing bench trials first, that is, treat a small amount (say 1L or even 100 mLs) of their wine first with a proportionately small amount of their desired additive. This way you can fine-tune the amount of an additive you want to introduce to get the desired effect but without over-doing it.
My guess is that you’re going to want to add around 5 mLs egg white per liter or so of wine, since you do seem to have some pretty tannic wine. It doesn’t hurt to start there. You can always add more if you need to, that’s the beauty of egg white fining. If you have 100 mL graduated cylinders and some small pipets (little tubes with measured graduation on the side, which allow you to suck up and dispense small amounts, even fractions of a millileter of liquid) you could even do bench trials in 100 mL sizes, and try 0.5 mLs per 100 mL of wine. Then try more and possibly less to see if you like a better effect. Whether you do a bench trial first or just choose to treat the whole lot, here’s the basic procedure:
•Carefully break your egg open and separate the yolk from the white. Save the yolks for something else, perhaps crème brûlée?
•Measure out the desired amount of egg white. Add a pinch of table salt per egg white used. If the egg is too viscous or difficult to measure, sometimes I agitate them gently with a fork first, without aerating, to break up the ropy proteins. The idea is to distribute the egg white, not to create a foam.
•For every egg white used, add about 2–3 mLs of water to help further “liquefy” the egg white and form it into a solution you can measure.
•Measure this solution (taking into account how much water you added) and add the desired amount (if you’re doing bench trials, use your pipets here) to your wine.
•Gently stir the wine with the egg white solution added, for about 1–5 minutes or until you feel the container has received a good mix. A 100 mL bench trial would take about 20 seconds whereas a barrel would take about three minutes with a big barrel-stirring wand (the kind with a blade on the bottom).
•Cover up or bung up your container of wine and let the egg whites do their thing; they will naturally glom on to the tannins and bitter phenolics and will form a layer of fluffy solids at the bottom of your container.
•After about two weeks, carefully rack your clarified wine off of this layer and voila! You can always taste a sample from the top of the container after about a week of settling to check if you think you’ve added enough egg white. If not, dose the container again with some additional egg white, stir and let settle out again until you are happy.
Other proteins to try (which remove tannins and bitterness) include products that contain gelatin, isinglass or casein (milk protein). There are lots of different commercial preparations available to winemakers online or in their local home brewing shops, but since I always have eggs around the house I tend to head there first.