Bizarre Hydrometer OG Reading

[FiddlersGreen87]

I brewed an English Mild today, and during the process I checked my Pre-Boil OG on my hydrometer just to see how the mash went. Well I was shocked to get a reading of 1.008. I can't make heads or tails of it. I even tasted the grains, as I usually do, after sparging and if there's any sweetness that's my first indicator something's off. The grains were completely flavorless. I went a head and boiled it anyways, chilled it, and took a Post-Boil OG reading because I know 1.008 is absurd. Well it came out at like 1.038 (estimated was 1.037).

Obviously everything's all good, but I can't figure out what would of caused such a bizarre reading. Any thoughts?

Couple of variables to rule out
-Hydrometer accurately reads 1.000 in plain water
-Temperatures for strike water/sparge were spot on and factored in grain/mash tun temps.
-Grain was crushed this morning right before the brew
-Hydrometer has read accurately in the past too

I can't think of any other factors, but if I do I'll add them. I'm just more curious for my own knowledge.

Thanks!

 

[LLBeanJ]

I'm assuming that the wort was cooled or you corrected for temp. All I can think of is that your wort was not mixed well and you got a diluted sample from the sparge. Other than that, I got nothin'.

 

[brick_haus]

Gravity readings are only correct at 60*F. If your preboil sample was hot when you took the reading, thats the issue. Hot sample = low gravity readings.

Nothing else makes sense.

 

[FiddlersGreen87]

I hear yah in regards to temp correction. I did the correction and it came out at 1.017 I think from what I remember. Still way off. I mean you are right, hot temps = low readings, but still way more skewed than they should be.

Edit - You know the more I've thought about it, maybe my temperature reading was off and my sample was even hotter than I thought or at a certain temperature an accurate reading can't even be compensated for by a calculator. I've plugged in my gravity at 159 degrees and it still only reached 1.028... Oh well, I guess I'll just let it go and take readings later on.

 

[acidrain]

Unless the temp is at least close (within 30F), the temp calculators are worthless.
If you want to measure hot wort, get a refractometer.

BTW, if you really did measure at nearly 160F, check your hydrometer for cracks... high temps destroy hydrometers, and therefor destroys beers.

 

[FatDragon]

I put an ice pack (but ice works way better when I've got room in the freezer for a tray or two) in a mixing bowl and put my hydro sample in a smaller stainless mixing bowl that floats in the ice water until it reaches reading temps. It's a bit of a pain and I often skip pre-boil reads to save the effort (and there are certainly better ways to do this), but reading anywhere above 85 or 90 is an exercise in futility even if you try to correct for temperature.