What would cause a low SG reading?

I bottled my first brew today and started my second. It is a Brewers Best Weizenbier. Followed directions (2 cans of wheat malt extract) and boiled 55 min with bittering hops and an additional 5 min with finishing hops. When I took my starting gravity reading it was 1.040, directions say 1.048-1.052. Why was the reading this low? My first brew (German Altbier) was within .002. It took 1 1/2 hours to cool the wort down to 70*F when the reading was taken. Could taking so long to cool be the cause?

Any number of things might cause this... the cooling issue isn't one of them.

When we talk about gravity, we're referring to the concentration of sugars in water. What a lower than expected gravity says is that there are a fewer amount of sugars than expected, or there is more water than there should be (but the right amount of sugars).

My thinking is that (one of the following):
- you didn't get as much extract out of the cans as you could have. Next time try using a ladle and scoop some of your boiling water into the cans, slosh around, and pour out. You can use a spatula to scrape the sides of the cans as well. Get as much of that extract out as humanly possible. (too little sugar, correct amount of water)
- you mis-measured your water and added to much, or your boil wasn't vigorous enough to boil off the amount of water that the recipe projected, resulting in more volume of wort than the recipe suggests. (correct amount of sugar, too much water)
- the recipe is wrong.

Whatever the case, relax It's still gonna be a tasty homebrew.

Did you take the gravity at 70F? The hydrometers are calibrated at 60F. You would have to take the reading at 60F or use a conversion factor for 70F with a quick net search you can get the conversion factors, or there should have been a conversion chart with your hydrometer.
Was your volume more than 5 gal? If your batch was for 5 gal and you ended up with a larger volume that would cause it....
Taking too long to cool would not hurt nothing unless the sugars were not completely dissolved and settled give it a good stir before taking a sample but this is usually not a problem unless you had a late addition that did not dissolve well.
Good luck

If you topped off, you need to stir well before taking the reading; the sugars tend to stay at the bottom, so the wort at the bottom has a much higher gravity than the stuff at the top (which is mostly just the top-off water). Just give it a coulple of good stirs.

Nothing to worry about doing now, the yeast will find the sugars. Honestly, you don't *really* need an OG reading for extract if you followed the recipe.

Thanks for the replies.
When brewing we warmed the cans of WME (wheat malt extract)and used a spatula to clean them out, transfer to the bucked was done very aggressively, lots of splashing and even had a small amount of foam. As far as amount of water goes, the water line is at the 5 gal mark of the bucket. I tested the hydrometer this morning with plain water and it read 1.000 so I'm not going to wory about it. Thanks for helping out a newbee.

As long as you are doing extract or extract with specialty grains, your hydrometer is most useful in checking the final gravity. Differences in OG can only be due to volume or mixing problems, because all of the sugars make it into the fermenter. [I rinse out extract bags/buckets with boiling water] Unfortunately, many people under-mix because of oxidation concerns and get bad readings. Just prior to pitching the yeast is the only time oxygen in the mix is a good thing.

slowspoke said:

Thanks for the replies.
When brewing we warmed the cans of WME (wheat malt extract)and used a spatula to clean them out, transfer to the bucked was done very aggressively, lots of splashing and even had a small amount of foam. As far as amount of water goes, the water line is at the 5 gal mark of the bucket. I tested the hydrometer this morning with plain water and it read 1.000 so I'm not going to wory about it. Thanks for helping out a newbee.

Click to expand...

My guess is that you didn't get the wort mixed well enough with your top off water. I bet your beer will turn out just fine