Extra pressure in the fermenting wine

 

The latest home brew is coming along. The gas produced by the yeast bubbles out quickly. It occurred to me that the pressure on the inside must be greater than the pressure on the outside by an amount measurable by the U-tube airlock. When a bubble is released, it does so through a column of water 8cm high. Pressure in a fluid = height x density x g. Density of water = 1000 kg/cubic metre. So extra pressure = 0.08 x 1000 x 10 = 80 N/m^2