"The wood I plan to use will be 1" thick. "

Still likely to sag under the weight of bottle of liquor, even with only a 24 inch span.

Water weighs right about 8 pounds per gallon, and liquor is not going to be a whole lot lighter.

A hardwood shelf might make it if it is a stronger wood, but pine or softwoods are likely to sag.

The thick shleves are also laible to look out of place and be expensive (hardwood is sold in 'quarters' of thickness.

4/4 wood is 4 quarters thick, or one inch.

It is also sold rough on all 4 sides.

To net out 1 inch wood require at least 5/4 wood.

You might consider using just plywood for the bulk of the shelf and a front and rear edging of a stronger hardwood to stiffen the shelf.

A section of ash or oak 1.25 inches high and only 3/4 thick on the front and back edges should be adequate.

Since the shelf surface does not really show (except when you remove a bottle) you can just match the color of the hardwood trim closely and have it look good without being as concerned with the figure (AKA 'grain') of the wood.

Use hardwood for the sides, bottom, and top since they show more (especially if the bottom will be used as a shelf for glassware).