"Iain William Wiseman" > wrote in message
...
> Hi,
>
> I am very new and know little physics,
>
> Do I need a gallon demijon for a gallon of wine or can I use a bigger one.
>
> Thanks, sorry it is a silly question
>
> Iain
> New Zealand

The answer is basically that you need a bigger one. How much bigger is not
so easy to answer. If you use your carboy as a primary, I prefer a bucket,
then you only want it 2/3's full. During secondary, you will want it filled
much more. Maybe half way up the shoulder. When you bulk age, you want it
filled up into the neck, within 1 inch of the airlock. As you can see, you
cannot use one size for a batch or you will need to do some kind of
adjusting. I like to keep an assortment of sizes so I can use what is best.
I use 12, 6.5, 6, 5, 3, 2.8, 1, and 1/2 gal sizes and have many of each.
But then I have been collecting them for 30 years and my insanity is still
growing. If yours is just taking wing, collect as many 1 gal jugs as you
can get your hands on (you can always go to several smaller jugs) and pick
up the larger ones as you can.

Ray