What went wrong (OG came out low)

beerguy2009 · 03-01-2010, 01:14 AM

I just finished brewing a Brewer's Best Engilsh Pale Ale kit and the OG came out low.
Here is what I did.
The recipe has you boil 2.5 gallons of water to make the wort. I used 3 gallons instead. I steeped the grains and added the DME, hops, and LME per the schedule. I added Irish Moss the last 15 minutes of the boil.
I then cooled the wort and added enough clean water to raise the total volume to 4 gallons. The recipe said the OG should be 1.042 to 1.046 and the total volume should be 5 gallons. The OG of my batch came out at 1.042 with 4 gallons total volume. I did add more water to bring the total volume to 4.5 gallons and the OG is now 1.040 (thought I should add water to get close to the total volume).
Why is the OG coming out on the low side? Is if because I used 3 gallons instead to 2.5 for the boil? What else may cause that?

snowbeer · 03-01-2010, 01:18 AM

Either the kit instructions are wrong, you measured wrong, or you didn't steep at the right temperature.

In any case, your beer will likely be just fine and if you didn't measure it you wouldn't know the difference!

cravej · 03-01-2010, 01:38 AM

Did you stir it up well before taking the reading? Mine was off by .012, before I realized I was measuring the lighter liquid at the top.

manticle · 03-01-2010, 06:16 AM

Quote:

Originally Posted by beerguy2009

I just finished brewing a Brewer's Best Engilsh Pale Ale kit and the OG came out low.
Here is what I did.
The recipe has you boil 2.5 gallons of water to make the wort. I used 3 gallons instead. I steeped the grains and added the DME, hops, and LME per the schedule. I added Irish Moss the last 15 minutes of the boil.
I then cooled the wort and added enough clean water to raise the total volume to 4 gallons. The recipe said the OG should be 1.042 to 1.046 and the total volume should be 5 gallons. The OG of my batch came out at 1.042 with 4 gallons total volume. I did add more water to bring the total volume to 4.5 gallons and the OG is now 1.040 (thought I should add water to get close to the total volume).
Why is the OG coming out on the low side? Is if because I used 3 gallons instead to 2.5 for the boil? What else may cause that?

First you changed the recipe so it's not surprising you would get a different gravity reading to that suggested. Presuming the grains are specialty grains and you're not doing a minimash, water tempterature should make little difference here.

You may have read wrong or your hydrometer might be out. It's also highly possible that it was just a temperature issue: what was the temperature of the wort when you measured it? Hot wort gives lower gravity readings so you may have been spot on but read it too hot. You can use hydrometer correction calculators - here's one: http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html. Usually correct for 20 degrees celsius or whatever the faranheit equivalent is. Your hydrometer should read 1000 in 20 oC distilled water so calibrate it.

Being an extract brew, correcting low gravities is as easy as adding in a touch more dry or liquid malt or dex if you want to balance out the maltiness.

beerguy2009 · 03-01-2010, 04:17 PM

Quote:

Originally Posted by manticle

First you changed the recipe so it's not surprising you would get a different gravity reading to that suggested. Presuming the grains are specialty grains and you're not doing a minimash, water tempterature should make little difference here.

You may have read wrong or your hydrometer might be out. It's also highly possible that it was just a temperature issue: what was the temperature of the wort when you measured it? Hot wort gives lower gravity readings so you may have been spot on but read it too hot. You can use hydrometer correction calculators - here's one: http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html. Usually correct for 20 degrees celsius or whatever the faranheit equivalent is. Your hydrometer should read 1000 in 20 oC distilled water so calibrate it.

Being an extract brew, correcting low gravities is as easy as adding in a touch more dry or liquid malt or dex if you want to balance out the maltiness.

So does having 3 gallons for the boil instead of 2.5 change the SG? I had the same problem with lower than expect SG with the last batch that I also did a 3 gal boil instead of 2.5. Also since I add dex to carb the beer I am assuming I can add dex to up the OG if nessessary without changing the beer too much? Does using Irish moss have anything to do with it?
Just trying to get a better understanding since I am still rather new to brewing.
BTW the grains were specialty grains.

TipsyDragon · 03-01-2010, 04:34 PM

the 3 gallons in the boil will not affect your OG. it will lower your boil SG which will raise the amount of bittering you got from the hops. my guess is the extract settled to the bottom and you drew your sample from the top of the pot. the irish moss will not affect your OG reading. the only thing it does is make your beer more clear.

wyzazz · 03-01-2010, 05:04 PM

+1 TipsyDragon is right. Use the SG that came with the kit to go by, unless you stirred that top off water with a paint mixer for 5+ minutes it wasn't mixed all the way up, hence the lower reading on your hydrometer. No worries though, those yeasties will mix it up for you during fermentation.

manticle · 03-02-2010, 01:18 AM

Quote:

Originally Posted by beerguy2009

So does having 3 gallons for the boil instead of 2.5 change the SG? I had the same problem with lower than expect SG with the last batch that I also did a 3 gal boil instead of 2.5. Also since I add dex to carb the beer I am assuming I can add dex to up the OG if nessessary without changing the beer too much? Does using Irish moss have anything to do with it?
Just trying to get a better understanding since I am still rather new to brewing.
BTW the grains were specialty grains.

Naturally having a higher liquor to sugar ratio will have an effect on gravity. I'm not sure whether by as much as you noted - I'm a metric man and the difference between 2.5 and 3 gallons is not immediately obvious. Since you ended up with less than the recipe I would have thought it would have compensated at some point but without converting and plugging through a spreadsheet I can't say exactly. My main point there though was that if you change a recipe, you will likely get differences in the final product.

My other points are probably more pertinent in this instance though - the temperature of the wort when you took the reading and the accuracy of your hydrometer. Unthorough mixing as mentioned above by several posters can also play a role in getting an unexpected reading.

Irish moss won't have any effect.