METHOD FOR PURIFYING DISTILLED SPIRITS

Abstract

A method for purifying distilled spirits includes cooling a distilled spirit to a temperature at which contaminants in the selected distilled spirit crystallize. The cooled, selected distilled spirit is passed through a first hollow fiber permeable membrane having openings smaller than a size of the crystallized contaminants.

Claims

1. A method for purifying distilled spirits, comprising: cooling a distilled spirit to a temperature at which contaminants in the distilled spirit crystallize; and filtering the cooled, distilled spirit through a first hollow fiber permeable membrane having openings smaller than a size of the crystallized contaminants.

2. The method of claim 1 wherein the cooling is performed at a rate of at most 2 degrees C. per hour.

3. The method of claim 1 wherein the temperature is 20 degrees C.

4. The method of claim 1 further comprising filtering the distilled spirit through an activated carbon filter prior to the cooling.

5. The method of claim 4 wherein the filtering through the activated carbon filter is repeated a plurality of times.

6. The method of claim 5 wherein the filtering through the activated carbon filter is repeated between two and nine times.

7. The method of claim 4 wherein the activated carbon filter is in block form.

8. The method of claim 7 wherein a pressure of the selected distilled spirit prior to the filtering in the activated carbon filter is at most 2 pounds per square inch.

9. The method of claim 1 wherein the filtering through the first hollow fiber permeable membrane is performed using compressed gas at a selected pressure to urge the cooled distilled spirit through the first hollow fiber permeable membrane.

10. The method of claim 9 wherein a pressure of the compressed gas is 20 pounds per square inch.

11. The method of claim 1 further comprising filtering the cooled, membrane-filtered spirit through a second hollow fiber permeable membrane having openings smaller than openings in the first hollow fiber permeable membrane.

12. The method of claim 11 wherein the openings in the first hollow fiber membrane have a lateral pore size of 0.1 microns.

13. The method of claim 11 wherein the openings in the second hollow fiber membrane have lateral pore size of 0.02 microns.

14. The method of claim 1 further comprising diluting the selected distilled spirit to a predetermined alcohol concentration with water prior to filtering through the activated carbon filter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a flow chart of an example process for purification of GNS or NCS according to the present disclosure.

DETAILED DESCRIPTION

[0024] An example method according to the present disclosure may be better understood with reference to FIG. 1. The example process begins with the selection of the base distilled spirit at 10. The base distilled spirit may be distilled through processes known in the art, e.g., fermentation of sugars, then pot or column distillation of ethanol. In some embodiments the base distilled spirit may be acquired industrial neutral spirits.

[0025] The base distilled spirit is diluted at 14, using filtered water or other clean water supply at 12, to the desired alcohol content by volume. Multistage reverse osmosis of water may be used for the supply of dilution water 12.

[0026] The diluted base distilled spirit may then be filtered, at 16, through one or more passes through one or more activated carbon filters. The activated carbon filter(s) may be block type or granular activated carbon. In the present example embodiment, block type activated carbon may be superior to granulated type filters in order to reduce sediment tailings. The flow rate may be limited to about 0.5 gallons per minute (gpm) for a 10 foot long, 2.5 foot square cross-section block activated carbon filter element. The pressure of the diluted distilled spirit ahead of the activated carbon filter should be at most about 2 pounds per square inch (psi).

[0027] Filtration 16 may be repeated, in the present example embodiment, 5 times. A range of number of filtration passes may be 1-10.

[0028] The filtered, diluted GNS or NCS may then be transferred, at 18. into one or more selected volume, e.g., 5 gallon (20 liter), stainless steel pressure containers. After filling with filtered, diluted spirit (hereinafter the liquid), the pressure containers may be slowly cooled, at 20, (e.g., at 2 C. per hour) to a final temperature of 20 C.

[0029] Once the liquid in the pressure container(s) is cooled to the foregoing temperature, the pressure container(s) is/are pressured with filtered compressed air or other compressed at a pressure of, for example, 20 psi to displace the cooled liquid from the pressure container(s). The displaced liquid may then be passed, at 22, through a hollow fiber membrane. The hollow fiber membrane may be made from, for example, cellulose acetate, polysulfone, polyethersulfone, and polyvinylidene fluoride. The lateral pore size of the membrane may be about 0.1 micron. The lateral pore size may be confirmed, for example, by evapoporometry.

[0030] A continuous, U shaped arrangement of hollow fibers may be used in the membrane. After passage through the hollow fiber membrane at 22, the liquid may be returned to room temperature, and then cooled again (e.g., at 2 C. per hour) to 20 C.

[0031] The cooled, hollow fiber membrane-filtered liquid may be further filtered, at 24, through a 0.02 micron hollow fiber, semi-permeable membrane. The further filtered liquid may then be returned to room temperature, tested for pH and final ABV, and then bottled, at 26.

[0032] The foregoing method may take advantage of a number of physical properties. Carbon filtering is an effective method for removal of volatile organic compounds (VOCs) and other contaminants. The slow cooling of the liquid induces crystal formation in contaminants that would in the absence of such crystal formation be too small for interaction with the carbon filter and the hollow fiber membrane. At 20 C. the contaminant crystals are large enough so as not to be able to pass through the 0.1 micron hollow fiber membrane and 0.02 hollow fiber, semi-permeable membrane and the resultant solution is pleasant to taste.

[0033] Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. 112(f), for any limitations of any of the claims herein, except for those in which the claim expressly uses the words means for together with an associated function.