This is good to hear!
In your photo, I didn’t see a stick on thermometer (maybe it’s on the back side). If you don’t have one, consider getting one. Another thing you could do is add lines on the Little BMB to indicate 3 quart, 1 gallon and 5 quart.
Knowing how much wort is in the fermenter will help with understanding your OG/FG measurements.
During active fermentation, the temperature on the stick on thermometer will likely be lower than the temperature in the wort. How much lower appears to be specific to your environment. Some people claim 5+ degrees difference. I found mine to be 2-3 degrees.
Here are some additional ideas / notes based on a couple of years of actually brewing very small (one gallon) batches. I stopped brewing them at the start of this year and promised myself to stop talking about them by the end of March (Over time, I have seen that experience matters when giving advice on a particular batch size).
- I haven’t see a one gallon NB kit that lists OG in the instructions.
- Be careful about using the 5 gallon extract kits for missing information, they can be “close”, but they can also be “different enough”
- There are ways to calculate an OG range for the one gallon kits (if you are interested, send me a PM).
When taking OG/FG measurements with very small batches sizes, very accurate water/wort volume measures matter. A one cup (8 oz) difference in a one gallon (128 oz) wort is a 5% difference. A one cup difference in the fermenter will result in a measurable difference between the estimated OG and the measured
When I first saw your photo in your original post, it looked like it had more than a gallon of wort in it. This image is a closeup of your fermenter (left side) with my fermenter and scale (right side). It looks like there was more than one gallon of wort in your fermenter. This would explain some (most?) of the OG measurement you took.
In the end, your first batch turned out good - which is all that matters for the 1st batch!