If you have a partially finished bottle of wine and you want to prevent the wine from oxidizing, you can use a wine pump. Many different styles are sold. They are usually hand-powered pumps that are used to lower the pressure in a wine bottle so there is less oxygen in the bottle. But how well do they work? We decided to do some tests. The tricky part was how to measure the pressure in the bottle. We ended up drilling a hole into the side of a wine bottle with a special drill bit made for drilling glass. We inserted one of our stopper stems with a Luer lock fitting in the hole, and sealed the hole with sealant. We used our Gas Pressure Sensor to measure the pressure.
We tried two different models of wine pumps. Two sample graphs are shown below.
The top graph shows one model of wine pump. Note that the pressure is quickly reduced to a little less than a half atmosphere. It is difficult to get much lower pressure with these pumps.
We were curious if the pumps really held the pressure. The second graph is a two-day run with a different model of pump. Note that the pressure again is just a little less than half an atmosphere.