How To Read A Fill Level

What does the fill level tell you about a bottle?

How To Read A Fill Level
Quick reference guide to fill levels.

We always try to indicate the fill level of whisky or spirit inside old and rare bottles and our handy diagram is a useful guide to the most commonly used fill level terms. But what is a ‘good’ fill level and why does it matter?


How much does fill level matter?

Our auction team carefully inspects every bottle we receive so that the listing can be described in detail. We include information about the bottle’s condition and its fill level too.

Bidders should check the fill level on the photo and under the condition statement.

The fill level can affect the price a bottle achieves at auction as it gives an indication of how much liquid remains in a bottle.

Most collectors and whisky enthusiasts prefer to buy bottles with higher fill levels, so these tend to achieve higher prices at austion. This means that if the fill level isn’t your main concern you will be able to pick up plenty of bargains.


What causes different fill levels?

A low fill level usually indicates that some of the original liquid has been lost. This may be because there has been a leak in the past: use our zoom feature to look closely at the closure for any indication that there has been a leak, you can also check the label for old stains.

More often there has been a slow evaporation over time. A small amount of evaporation through the tiny gaps in the closure is to be expected with older bottles and does not affect the price.

Remember to check the bottle against an identical one.

It could be that the level simply appears to be abnormally low (or even high) but is in fact perfectly normal. You’ll see this occasionally when a brand use the same bottles for 75cl and 70cl fills or when they use certain types of decanter.


Should I worry about a low fill level?

A slightly low fill level is perfectly normal with older bottles, particularly those sealed with porous or degraded closures. This is a reassuring sign that all is as it should be.

We see low levels less often in bottles sealed with secure screw caps and spring caps. This is one reason why these closures are so popular.


When should I be concerned?

So, a low level in itself is not something to worry about. On the other hand do watch out for unexpected cloudiness in the liquid that does not eventually disappear or settle.

We always check whether the cloudy haze in a bottle is reversible. If the haze eventually disappears when the whisky is warmed and shaken it’s likely it was stored for a prolonged period at a cold temperature. The presence of a reversible haze does not indicate there is any fault so should not cause any concern.

If the cloudiness is not reversible then it may be that there has been too much evaporation and the proportion of alcohol to water has dropped. We all know that high alcohol can be relied upon to kill a broad range of germs, including bacteria, viruses, and fungi. The cloudiness might indicate a growth of bacteria because there is not enough alcohol in the liquid. It won’t taste very nice and it might make you ill.

At Whisky.Auction we do not accept cloudy whiskies.


My bottle arrived and it contains sediment or particles. Should I worry?

In contrast we do accept whiskies with sediment to the auction.
Naturally occurring sediment may appear in older whiskies before all distilleries and bottling plants switched to demineralised water.
So, the presence of sediment may merely indicate a long aged whisky.


Can a fill level be too high?

Again, check your bottle against other identical ones. You would not expect to have an abnormally high level or different coloured liquid.


What if the fill level is not visible?

Some spirits are bottled in ceramic decanters so the fill level of the liquid is not visible. This makes it impossible to accurately inspect the bottle’s contents so we try to get an indication by weighing the bottle and we include the weight in the condition report.


How to do I protect the fill level when storing my bottle of whisky?

Simply store your whisky bottles upright and away from direct sunlight and heat.

If you have a bottle with a fragile closure, or you plan to store your bottle for an extended time then you can take measures to make the closure more air tight.

In the past collectors used a variety of measures such as dipping the closure in wax or sealing it with Sellotape. However there are disadvantages to both: wax is not easily removed without damaging the original closure. This is fine unless you intend to sell your bottle in future. Sticky tape has an acid that degrades and becomes brittle over time.

After experimenting with a variety of options, at Whisky.Auction we use a non toxic semi-transparent, stretchy self sealing film that you can cut to size and stretch around the neck of a bottle (it is normally used to seal and protect laboratory containers). The film provides a tight, chemical resistant seal. It is particularly useful for long distance shipping.

Unfortunately this film doesn’t prevent a bottle leaking under extreme conditions but it does help slow down evaporation.