In the past couple of weeks two people have told me that they never see little bubbles rising in their containers of fermenting cucumbers. Usually bubbles start appearing after three or four days of brining. I explained that the bubbles may be hard to see because they’re very small. Their movement is most noticeable if the pickles are in a clear glass jar and the jar is moved. The bubbles are usually easy to see at the top of the brine, where they collect. If the brine spills over the top of the jar, you know it’s because gas has bubbled up inside and expanded the volume of the brine.
In the picture above, the cucumbers have been brining for about four days. You can see the bubbles at the top of the brine and a little further down in the gallon jar, just above the point where the jar begins narrowing.
Notice that I’m not using a plastic brine bag to hold down the cucumbers; instead I’ve laid the biggest cucumbers crosswise across the top to hold down the rest. Some of the dry spices are floating; that’s okay. But the brine is pushing grapes leaves too close to the surface, where they might attract the wrong microbes. After taking this picture, I tucked the grape leaves down around the cucumbers.
Approximately a day after I took this picture, a yeast scum began forming at the top of the jar. The yeast isn’t essential to the brining process, but it’s a sign that all is well. I skim off the scum when it gets heavy.