Second hydrometer reading below water mark

Working on my first batch here and had a problem with my second hydrometer reading after racking to the secondary this afternoon. The batch is an IPA and the OG was 1.044. Fermentation took off steady after 2 hours (made a yeast starter) and continued for 8 days until the blow off was producing less than 1 bubble per minute. When I took the second hydrometer reading the reading was below the 0 mark. I tried twice and got the same result. I've done multiple hydrometer readings in laboratory settings and so I don't believe it's a misread on my part, and when measured with water at STP the reading was spot on. I tried finding a thread that touched upon this subject, however, came up with nothing. So I hope somebody has an idea of what the issue could be. Any advice/info would be greatly appreciated. Thank you!!

Do you mean you read below 1.000 on the hydrometer? If that's the case you either mashed at way too low of a temp if this was an all grain batch, or you have an infection or possibly just fermented too hot and caused over attenuation. If your reading was correct this beer is going to be very thin and possibly broken. Might even taste like jet fuel if fermentation temp is to blame. Was this batch extract or all grain and did you control fermentation temps?

This was an extract batch and I steeped some specialty grains as well. The fermentation temperature was controlled reasonably well with the temperature never getting below 68 and never above 70. I checked the temperature often.

As for the reading on the hydrometer it was below 1.000; literally bobbing out of the sample. The taste didn't have any off flavors and honestly was reasonably close to what I would expect it to taste like.

While its certainly possible to ferment below 1.000, its fairly rare for beer, especially an extract batch. Just for reference, what was the recipe and yeast you used? If there was also a lot of sugar, or you decided to use a big saison yeast, it could maybe get down that far. Otherwise, assuming the measuring was correct, then infection might be the next place to look, since some wild yeasts can ferment the sugars normally left behind by brewer's yeast.

Before you worry though, just wanted to check a few things first. Since you say it was bobbing, I'm assuming you put enough sample in your testing jar (hey, I've made that mistake before ). Did you let the sample sit for a bit before testing it? If it had just finished fermenting, it might have a fair amount of CO2 in solution that could have nucleated on the hydrometer, causing it to rise. If you let it sit for an hour or so (or shake it and then let it sit), you can get some of that CO2 out of solution before measuring. The other thing to check is to make sure that the hydrometer isn't resting up against the side of the container. Since it sounds like you've done this before you've probably already done that, but just trying to come up with options now.

That is a low reading for sure. And you said you double checked the calibration with water so the hydrometer appears to be working fine. EricPete18 has some great ideas, I'm leaning towards some type of infection. Can you post a picture of the top of the beer? Might give some insight to an infection.

There should've been enough sample in the graduated cylinder. The sample may not have been sitting out long enough as you've mentioned... but at this point would it be the smart bet to wait it out and just see what turns out rather than risk trying to get another sample out of the secondary?

If it is infected you can't do anything about it. So let your sample sit in the wort wait it out. As mentioned before maybe the CO2 is messing with the reading.

Good luck! Please post the final results.

Thanks for the advice everyone. I will post the results!