What it is, why it matters, and how much is too much
Ullage is the air space in a barrel above the wine. Some people call it headspace. In fortified wine, ullage matters because it changes how quickly your barrel ages and how much oxygen the wine is exposed to.
A little ullage can be useful. Left unchecked, it can push the wine too fast.
What does ullage mean
Ullage is simply the gap between the wine level and the bung.
The word itself is a great clue to the concept. Ullage comes via French winemaking language, from ouillage, which is the act of topping a barrel up. It is linked to the idea of filling a barrel right up to the bung, sometimes described as filling it “to the eye”.
So ullage is both
The space that appears when the barrel is not full
And the traditional practice of topping up to manage that space
Why ullage matters in fortified
Fortified wine is built on controlled ageing. Oxygen is part of the process, but control is everything.
It helps to remember that ullage oxidation is not the same as oxidation through oak. Oak allows slow, steady oxygen exchange through the barrel itself. Ullage adds extra air contact in the headspace, which can change the pace dramatically, especially in smaller home barrels.
How much ullage is too much
Our simple rule is no more than one quarter ullage.
The safest default for most home barrels is to keep the barrel topped up full, particularly for Muscat and Topaque where lift and freshness are easier to lose if the wine is pushed too quickly.
Our recommended method at home
Fill your barrel right up and leave it for 12 months.
Over that time, ullage will naturally form as the wine slowly concentrates and evolves. This gives your barrel a chance to settle into a steady rhythm before you decide how much ullage you want to maintain long term.
When to be more conservative
For really old barrels or very old wine, we do not recommend too much ullage. These wines are already beautifully evolved and they do not need extra oxygen exposure to build character. Too much headspace can push them past their best.
How we use ullage at the winery
In the fortified cellar, ullage is managed as part of style and progression, not left to chance. Our barrels are typically very old and have been producing fortified wine for decades, so the focus is steady, controlled development rather than rapid change.
We taste regularly, top up to maintain balance, and adjust for seasonal conditions.
Practical tips for home barrel owners
Check your barrel level regularly and top up before ullage creeps past the one quarter mark. If you are unsure, keep ullage on the lower side, especially for Muscat and Topaque.
Which styles suit a little ullage
Tawny can handle slightly more ullage than Muscat or Topaque, but it still needs to be managed and kept consistent.
If you want help dialling in your setup, make a note of your barrel size, where it is stored, and what style you are making. From there you can set a simple top up rhythm that suits your space and keeps ullage under control.
If you would like a tailored plan, you can book an in person or Zoom consultation with our winemakers. They will help you map out a topping schedule, style goals, and simple checks to keep your barrel healthy and your fortified ageing steadily.
