Quick answer
- Standard 750 ml wine bottles take #8 or #9 corks.
- #9 corks are 2 mm wider than #8, and long corks are 7 mm longer. Wider and longer means a better seal and longer storage.
- Agglomerated corks suit most home wine. Natural corks suit wines you plan to keep for 3 years or more.
Choosing a cork comes down to two questions: how long will you keep the wine, and what fits your budget? “You get what you pay for” holds true. But an expensive cork in a wine you will drink within three months isn’t a good deal either.
Cork Sizes
| Cork | Length | Width |
|---|---|---|
| #8 Regular | 38 mm (1.5 in) | 22 mm (0.87 in) |
| #8 Long | 45 mm (1.77 in) | 22 mm (0.87 in) |
| #9 Regular | 38 mm (1.5 in) | 24 mm (0.94 in) |
| #9 Long | 45 mm (1.77 in) | 24 mm (0.94 in) |
A standard wine bottle has an 18.5 mm neck opening. Every cork is wider than the neck and must be compressed by a corker to go in. That compression is what makes the seal. A #9 compresses more tightly than a #8, and a longer cork adds more sealing surface. Our rule of thumb is to use #9 long corks. They don’t cost much more, and any bottles you tuck away for longer will have the better cork.
Insert any cork so it sits just slightly below the rim of the bottle.
Types of Cork
Wine corks are made from the bark of the cork oak (Quercus suber), mostly grown in Portugal. The bark is harvested every 7 to 10 years without cutting down the tree.
Natural (Winery Grade)
Punched from the best pieces of bark, with no patches or fill. They can last 3 to 10 years or more, depending on quality and storage. They are the premium choice for wines you will age. See ABC Elite Series natural wine corks.
Colmated (Economy Grade)
Cut from less solid bark, with small voids filled with a cork and glue mixture. They cost less than natural cork and suit wines stored for up to a couple of years. Occasionally, a little cork dust from the filling shows up around the top of the bottle.
Agglomerated
Made from cork granules bonded with a food-safe glue. They are inexpensive and easy to use, and they suit wine stored for 6 months to a year or more. They are the most popular choice for home winemakers. We have kept wine for over three years under agglomerated corks with no problems. See agglomerated wine corks, #8 short agglomerated corks and micro agglomerated corks.
Synthetic and T-Top Stoppers
Synthetic corks look like natural cork and go in the same way. Bar-top (T-top) stoppers can be pushed in by hand and are great for fortified wines, spirits and bottles you open often.
Quick Guide
| Drinking within | Suggested cork |
|---|---|
| Up to 1 year | Agglomerated #8 or #9 |
| 1 to 2 years | #9 long agglomerated or colmated |
| 3 years or more | Natural #9 long |
Never use a cork that smells musty or mouldy, or one that is dried out.
Frequently Asked Questions
Do #9 corks fit standard wine bottles?
Yes. Both #8 and #9 corks fit standard 750 ml bottles with an 18.5 mm neck, using a corker.
Can I push a wine cork in by hand?
No. Standard corks must be compressed with a corker. Only T-top (bar-top) stoppers go in by hand.
Can I reuse screw-top bottles with corks?
We don’t recommend it. The glass between the threads is too thin to cork reliably.
Keep Reading
Need a hand with your batch? Call us toll-free at 1-877-668-6160 (Monday to Friday, 8:00 a.m. to 3:00 p.m. Eastern) or send us a message.
This guide is adapted from the ABC Crafted Series booklet Wine From Kits: What the Instructions Don’t Always Tell You. Always follow the instructions that come with your kit.