Some will argue that this process is a form of distillation, and is therefore illegal. As for my view, distillation involves the application of heat
to a liquid (beer, wine, mead) to create an alcoholic vapor which is collected and condensed to produce a more alcoholic liquid. In this case, the
alcohol is seperated from the base product. Freeze concentration on the other hand involves removing water in the form of ice from the base
product. Technically this probably shouldn't be considered distillation, but our government could create a law that considers it as such. At this
point, I have seen no evidence that this practice is illegal, although it may reside in a gray area of the law.
What is the point of this discussion? Well, freeze concentration may or may not be legal. It is up to you to decide if you want to take on the little
bit of legal risk that may be associated with this practice. I don't think you will attract any attention from the authorities unless you produce mass
quantities and bring attention upon yourself, or get caught trying to sell the stuff. Do it, but keep the volume down and don't attract attention.
With that said, time to get on with my process.
There are many ways to approach freeze concentration, and it took me a while to refine the process. My first attempt was with an Eisbock, and
the process was a complete mess although the Eisbock turned out pretty good. In that process, I used 1 gal food containers to freeze the bock
then tried to transfer the frozen mass to a similar container with holes in the bottom. Well, with the residual sugars and the alcohol, it wasn't the
solid block that I was expecting. Most of it made it to the target container, but I ended up with a syrupy mess on the counter. I then knew that I
needed to develop a closed system for the process.
It took a bit of thinking, but eventually I realized that I already had the tools needed to do the process. I have what is called a Tornado Tube, which
is a short tube with threads on both ends and a small hole in the middle. The threaded ends will fit many plastic soda bottles. In my area (N. Calif.)
the tube will fit 16 oz, 20 oz, 24 oz, 500 ml, 1 liter and 2 liter plastic bottles. I imagine it would be the same throughout the U.S. The Tornado Tube
can usually be found at American Science & Surplus and possibly at novelty or educational stores. At the AS&S site, do a search for Tornado.
My freeze concentration process is fairly simple, but needs a bit of trial and error to get a good feel for it. It might be a good idea to start with the
smaller bottles for your trial period and work yourself up to the larger bottles. You will need at least one empty bottle to collect the runoff.
Fill your clean bottles to no more than the original fill level. Freezing will cause some expansion and the mouth of the bottle needs to remain clear
or the runoff may get blocked. Place a clean cap on the bottle and place in the freezer. Do not lay the bottles down or the mouth will be blocked
with ice. Set them upright or on an incline so the neck and mouth of the bottle is free of liquid. Allow the bottles to freeze completely. Beverages
with high alcohol or residual sugars will not freeze into a solid mass and will give slightly when squeezed.
When your bottle is frozen, sanitize your Tornado Tube and collection bottle. Screw the tube onto the collection bottle first and then attach this to
the frozen bottle. Make sure you have a fairly tight seal and then invert the bottles. The process may work better if the bottles are at an angle
rather than standing straight up. Because of the alcohol and residual sugars, there should be some liquid that is ready to drain into the collection
bottle. If the volume is to large, the flow may stop. If this happens tip the bottles back towards horizontal and let the liquid slowly transfer to the
collection bottle. Once the initial flow has transferred, the process proceeds slowly. The ice has locked up most of the alcohol and residual sugars.
As the ice melts, the alcohol and residual sugars are released and flow into the collection bottle along with some of the water.
The initial and early runoff will be highest in alcohol and residual sugars. At this point you have several options. You can just collect a certain
portion of the runoff like a quarter or half a bottle. This will most of the alcohol , but some of the sugars and flavor components will remain locked
in the ice. For this reason, I prefer to process the beverage several times, until the runoff will not freeze enough to form a solid ice structure that
will be held back by the tube. It is helpful if the beverage you are using has some color to it at least while you are learning to use this process.
I usually try to leave behind about 20% behind each time through the process. At this point, the ice remaining should be clear or nearly so. Let
this ice melt seperately and taste it. It should have very little flavor and the S.G. should be 1.000 or very close to it. This would indicate that you
have little other than water to discard. If the water still has a strong flavor, it would be an indication that the process either wasn't done completely
enough or that the flavor component was water soluble and not alcohol soluble. If it is a solubility problem, there is little you can do about it. You
could always add it back to the runoff and reprocess, leaving behind less ice the next time to see if the results change.
Additional Notes
I now use this process primarily as a means to recover mead that is mixed in with the pulp (lees) of my melomels. There are a number of ways
to recover the mead in the lees and this process is how I deal with it. I try to estimate the volume of lees that will result from the fruit pulp and add
that amount to my desired final volume. It is a bit of a guessing game, as the volume of lees will usually be greater than that of the fruit. To fill a
7 gal carboy with clear finished mead, I may have an initial volume of 8 to 10 gal depending on the amount of fruit used. It is also important to
make sure that there is enough liquid mixed in with the pulp so that enough ice will form to act as a filter. If there is not enough ice formed you
will not be able to seperate the mead from the lees. This will take a bit of experimentation on your part to get the balance right. If the process is
working for you, you may consider lowering the liquid portion a little at a time. If you find that the process is not working because you have to
much pulp, additional water or mead can be added and then refreeze the bottle. Both of these options have worked for me.
In your initial trials with this process, it will be easier to use a finished or fairly clear mead, beer, wine or cider. Once you have a feel for the
process, you can attempt to recover your mead from the lees. A much better alternative than dumping the lees.
When I first started using the process, I would keep all of the batches seperate for sampling and comparison. I have found that the finished
product can be stored in plactic bottles in the refrigerator or freezer for quite some time without noticable degradation. Now days, I blend
everything into what I call the Monster Batch. Two liter bottles are filled and stored in the cooler until I can fill a seven gal carboy. Once the carboy
is filled, it will be aged until I get around to bottling. At bottling time, four gallons will be bottled and three will go into a three gal carboy. When
four more gallons have been collected everyting will be blended into a seven gal carboy again, and the cycle continues.
Some of you may wonder about oxidation, I know that was a concern of mine. I have not noticed any problems and if it existed, may be
complimentary due to the higher alcohol levels. If this is of concern to you, experiment with several batches using smaller bottles so your risk is
limited. If you are happy with the results, step up to larger bottles.