Product Use and Care
All products sold by Cork Supply are of the finest quality materials and production, and delivered to you in ready-to-use condition. By following the use and care guidelines below and complying with the bottling instructions from your glass suppliers and equipment manufacturers, you should enjoy successful bottling with our closures. While you are responsible for making any adaptations to fit your specific needs, Cork Supply representatives are available for additional guidance and troubleshooting. Should you require assistance, please contact your account representative immediately.
Natural Cork Closures
Nomacorc® Synthetic ClosuresScrew Caps
Natural corks from Cork Supply represent the finest, quality-assured materials and production. We deliver our premium natural corks to you in ready-to-use condition in sealed bags (of 1000 corks per bag) that have been sterilized with SO2.
By following the use and care guidelines below and complying with the bottling instructions from your glass suppliers and equipment manufacturers, you should enjoy successful bottling with our natural corks. While you are responsible for any adaptations you make to fit your specific needs, Cork Supply representatives are available for additional guidance and troubleshooting.
Before opening sealed bags of cork, it is important that you read these recommended corking practices.
Corker Jaw Type
- Use a four-segment sliding jaw type cork compression system. Roller or iris type jaws tend to cause wrinkles in the cork, which can result in leakage.
- Make sure corking machines are maintained to the manufacturers' recommended standards.
- Check to ensure there is smooth action in the compression stage.
- Check to ensure there are no nicks or other damage to the jaw segments.
- Ensure proper centering of the cork plunger, the cork and the bottle neck — this is critical to proper sealing and preventing damage to the corking equipment or corks.
- Ensure daily cleaning and sanitation of all cork handling surfaces, including hopper, feed tube, orienter and jaws.
- Ensure proper compression (for example, a 24mm cork should not be compressed to less than 16mm).
Cork Handling and Storage
- Do not open plastic cork bags until immediately before loading corks into the corking machine. No bags containing corks should be left open for any reason.
- Recover any corks from the corking machine after bottling is completed, and return them to the plastic bag or other closable container "dosed" with sulfur dioxide gas (SO2 vapor) and sealed tightly.
- Store corks in a cool, dry location — not in a bottling room or areas where barrels or chemicals are stored. Ideally, the temperature should be 60°F to 70°F and the humidity 50% to 70%.
- Do not use corks which have been stored for 6 months or more without first having Cork Supply make an evaluation of their condition for usage prior to bottling.
- Check new shipments of cork, as well as corks that have been stored for extended periods of time, for moisture content before use.
- Corks with an average moisture level below 5% should be discarded, or contact Cork Supply to have these corks rehydrated and repackaged in a sterile bag.
- Corks with average moisture content over 8% should be regarded with suspicion, as such moisture could support mold growth.
- Ensure the inner neck of the bottle is dry before bottling.
Internal Bottle Pressure
- Ensure the wine temperature is between 60°F to 70°F. If lower temperatures are used, the fill point should be adjusted down to compensate for expansion in the bottle when room temperature is reached. If the fill point is too high, less vacuum can be achieved.
- Make sure the vacuum system is properly controlled and maintained. Gauges that continuously display vacuum status at the corking head and provide online quality checks of corked bottles every 30 minutes (using a pierce test) are highly recommended.
- Keep bottles upright for 24 hours after corking.
- It is recommended that the above elements be combined to produce a net effect of no more than 3 psi internal bottle pressure at 68°F.
Nomacorc® Synthetic Closures
By following the simple guidelines below and adhering to the bottling recommendations from your glass suppliers and equipment manufacturers, you should enjoy successful bottling with Nomacorc closures. While you are responsible for making any adaptations to fit your specific needs, Cork Supply representatives are available for additional guidance and troubleshooting.
Storage of Nomacorc Closures
- Nomacorc closures are delivered packaged in a sealed, polyethylene bag containing 1000 units.
- Keep closures in a cool, dry, clean area if they are to be stored on site prior to use. Ideally, store them between 5°C (41°F) and 30°C (86°F), making sure to keep them out of direct sunlight and preventing them from contacting any liquids or natural corks.
- Don't open plastic closure bags until immediately before loading them into the corking machine to ensure they are clean of contaminants and do not absorb any sensory elements of the environment.
- Discard any remaining closures recovered from the corking machine after bottling is completed, in order to maintain hygienic conditions.
- Don't store extra bags of closures for longer than one year.
Bottles Used with Nomacorcs
- Use only quality bottles conforming to the CETIE or GPI standards on cork mouth finishes:
- 18.0mm-19.0mm, measured at 3mm in from the top of the bottle
- 18.5mm-20.0mm, measured at 15mm in from the top of the bottle
- 19.0mm-20.5mm, measured at 30mm in from the top of the bottle
- 19.0mm-21.0mm, measured at 45mm in from the top of the bottle
- Make sure bottles from different lots are uniform to ensure a successful filling run.
- Ensure bottle mouth and neck are thoroughly cleaned and dry.
- Understand that reused bottles (from a recycling source or other provider) can pose a challenge for all closures, including Nomacorc closures, as they come from different manufacturers and different glass molds resulting in variations in bottle height and bottleneck dimensions.
- Pay close attention to bottle fill levels and headspace pressures.
Corking Equipment used with Nomacorcs
- Any standard, well maintained corking machine may be used with Nomacorc closures, and special settings beyond those used with natural corks are not typically required.
- Nomacorcs perform best on four-jaw feeding systems used with a vacuum.
- Inspect the condition of the corking jaws prior to and during use.
- Don't use heated clamps with Nomacorc closures.
- Ensure proper centering of the cork plunger, the closure and the bottle neck — this is critical to proper sealing and preventing damage to the corking equipment or closures.
- For optimum mechanical and aesthetic performance when using Nomacorc closures, the recommended compression diameter settings on the corking jaws are between 16.0mm and 16.5mm. Please refer to your equipment manufacturer for your default settings. (On newer GAI and Bertolaso machines, the current default settings are 16mm.)
- Use extreme care when using manual corking machines with Nomacorc closures. Test to ensure the jaws don't damage the closures.
Bottling Process Used with Nomacorcs
- Remove several bottles from the conveyor after the run has begun, and check for any lipping, creasing or cutting (which could indicate future leakage).
- Keep the compression speed of the closure slow, while keeping the speed of the closure insertion into the bottle fast.
- Nomacorc recommends a maximum insertion of 1.0mm below the top of the bottle.
Ullage Pressure and Nomacorcs
- When closing bottles under vacuum, the pump should be set to -0.5bar (-6.75psi). For the ideal seal, monitor the pressure in the ullage (headspace) approximately ten minutes after bottling to ensure it is between -0.3bar (-4.35psi) and +0.3bar (+4.35psi).
- Be aware that the vacuum pump gauges may not accurately reflect the actual ullage pressure, so manual measurements through the closure into the headspace should be made with a pressure gauge attached to a thin needle.
Filling Height and Temperature
- Make sure fill levels comply with the bottle manufacturers' designated fill height and wine temperature (usually indicated at the bottom of the bottle) which is often 55mm, 63mm or 70mm as filled at 20°C (68°F) measured from the very top rim of the bottle.
- If the wine is to be filled at temperatures lower than 20°C (68°F), make fill height adjustments to account for eventual expansion of the wine.
- Insert Nomacorc closures into the bottles under similar room temperatures (close to 20°C (68°F)). Ideally, bring the closures themselves up to this temperature prior to use.
- Choose a Nomacorc length (36, 37, 38, 42, 43, 44 or 47mm) that, according to the fill height, will allow a minimum ullage (headspace) of 17mm at a wine temperature of 20°C (68°F) for a 750mL glass wine bottle.
- For a 1.5L wine bottle, the ullage or headspace height should be 27-30mm at a wine fill temperature of 20°C (68°F).
- Be aware that Nomacorc closures typically elongate an average of 2mm when being inserted into the bottle.