Any process which changes the character of the wine to the extent inconsistent with good commercial practice is not permitted on bonded wine premises. The processes listed in this section are approved as being consistent with good commercial practice for use by proprietors in the production, cellar treatment, or finishing of wine, juice, and distilling material, within the general limitations of this section: Provided, That when the specified use or limitation of any process on this list is determined to be unacceptable for use in foods and beverages by the U.S. Food and Drug Administration, the appropriate TTB officer may cancel or amend the approval for use of the process in the production, cellar treatment, or finishing of wine, juice, and distilling material.
Processes Authorized for the Treatment of Wine, Juice, and Distilling Material
| Processes | Use | Reference or limitation |
|---|---|---|
| Electrodialysis | To aid in the removal of tartrates | This process must not alter the vinous character of the wine. |
| Elimination of sulfur dioxide by physical process | To reduce the sulfur dioxide content of juice | Use of a physical process to remove sulfur dioxide from juice must not alter the basic character of the juice so treated |
| Ion exchange | Various applications in the treatment of juice or wine: | Anion, cation, and non-ionic resins, except those anionic resins in the mineral acid state, may be used in batch or continuous column processes as total or partial treatment of wine, provided that with regard to juice or finished wine; |
| 1. Such treatment does not alter the fruit character of the juice or wine. | ||
| 2. The treatment does not reduce the color of the juice or wine to less than that normally contained in such juice or wine. | ||
| 3. Treatment does not increase inorganic anions in the juice or wine by more than 10 mg/L. | ||
| 4. The treatment does not reduce the metallic cation concentration in the juice or wine to less than 300 mg/L. | ||
| 5. The treatment does not reduce natural or fixed acid in grape wine below 4 g/L for red table wines, 3 g/L for white table wines, 2.5 g/L for all other grape wines, 4 g/L for wine other than grape wine. | ||
| 6. Treatment does not reduce the pH of the juice or wine to less than pH 2.8 nor increase the pH to more than pH 4.5. | ||
| 7. The resins used have not imparted to the juice or wine any material or characteristic (incidental to the resin treatment) which may be prohibited under any other section of the regulations in this part. The winemaker may employ conditioning and/or regenerating agents consisting of water, fruit acids common to the wine or juice being treated, and inorganic acids, salts and/or bases provided the conditioned or regenerated resin is rinsed with water until the resin and container are essentially free from unreacted (excess) conditioning or regenerating agents prior to the introduction of the juice or wine. 21 CFR 173.25. | ||
| Metal reducing matrix sheet processing | To reduce the level of metals such as copper and iron in wine | (1) The active ingredient, polyvinylimidazol, must not constitute more than 40% by weight of the sheet. (2) Use of the sheet must not significantly alter the color of the wine. |
| Nanofiltration | To reduce the level of volatile acidity in wine (used with ion exchange) | This process must use permeable membranes which are selective for molecules not greater than 150 molecular weight with transmembrane pressures of 250 psi or less. |
| Osmotic transport1 | For alcohol reduction | (1) Use must not alter the vinous character of the wine (2) None of the stripping solution may migrate into the wine. |
| Reverse osmosis1 | To reduce the ethyl alcohol content of wine and to remove off flavors in wine | Permeable membranes which are selective for molecules not greater than 500 molecular weight with transmembrane pressures of 200 psi and greater. The addition of water other than that originally present prior to processing will render standard wine “other than standard.” Use shall not alter vinous character. |
| Spinning cone column1 | To reduce the ethyl alcohol content of wine and to remove off flavors in wine | Use shall not alter vinous character. For standard wine, the same amount of essense must be added back to any lot of wine as was originally removed. |
| Sulfide reducing matrix sheet processing | To reduce the level of sulfides in wine | (1) The active ingredient, polyvinylimidazol, must not constitute more than 40% by weight of the sheet. (2) Use of the sheet must not significantly alter the color of the wine. |
| Thermal gradient processing | To separate wine into low alcohol and high alcohol wine fractions | The fractions derived from such processing shall retain vinous character. Such treatment shall not increase the alcohol content of the high alcohol fraction to more than 24 percent by volume. The addition of water other than that originally present in the wine prior to processing will render standard wine “other than standard.” |
| To separate juice into low Brix and high Brix juice fractions | The low Brix fraction derived from such processing may be used in wine production. The high Brix fraction derived from such processing shall not be diluted with water for use in wine production. | |
| Thin-film evaporation under reduced pressure1 | To separate wine into a low alcohol wine fraction and into a higher alcohol distillate | Use shall not alter vinous character. Water separated with alcohol during processing may be recovered by refluxing in a closed continuous system and returned to the wine. The addition of water other than that originally present in the wine prior to processing, will render standard wine “other than standard.” |
| Ultrafiltration | To remove proteinaceous material from wine; to reduce harsh tannic material from white wine produced from white skinned grapes; to remove pink color from blanc de noir wine; to separate red wine into low color and high color wine fractions for blending purposes | Permeable membranes which are selective for molecules greater than 500 and less than 25,000 molecular weight with transmembrane pressures less than 200 psi. Use shall not alter vinous character. 21 CFR 175.300, 177.1520, 177.1550, 177.1630, 177.2440, 177.2600, and 177.2910. |
[T.D. ATF-299, 55 FR 24989, June 19, 1990, as amended by T.D. ATF-312, 56 FR 31081, July 9, 1991; T.D. ATF-350, 58 FR 52232, Oct. 7, 1993; T.D. ATF-371, 61 FR 21079, May 9, 1996; T.D. ATF-409, 64 FR 13683, Mar. 22, 1999; T.D. TTB-17, 69 FR 67644, Nov. 19, 2004]