If you need to update the configuration of a barrel group you can use the Measurement operation to do so. It will allow you to change the volume in any barrel, add/remove or swap a barrel in that group.
You can either click the icon highlighted in the screenshot below or click Operations > Measurement.
You'll be presented with the screen below that contains the current barrel list along with the current volumes in each.
Add/Remove a barrel
If the list of barrels in your barrel group need changing you can do so from the Barrel details section. You can click Add line and fill out the additional barrel code to input a new barrel to the group. To remove a barrel click the red X icon on the far right hand side of the window. This allows you to swap one barrel for another.
Change a barrel's volume
Changing the volume of the barrels in your group can be done in one of two ways. You can provide vintrace with the total volume of wine and allocate it across the barrels or let vintrace calculate the total volume based off the individual barrel volumes.
Work out volume from Barrel details
If you would like vintrace to calculate the groups total volume, you will need to supply a Fill status for each barrel. The options available are Full, Three Quarters, Half, Quarter, Specify and Empty. These will be calculated based off the capacity of the barrel but you can use Specify to manually type in your volume.
I know the volume of wine
If you have the total volume of the wine you can enter that value in the New Amount field. You then have the option as marking a barrels Fill state as Full, Partial (remaining), Specify or Empty. Once you've marked all of barrels you can click Apportion Partial and the amount in the Partial barrels will be calculated based off the remaining volume.