Low S.G.?

[TinmanDan]

I've brewed four extract batches using ingredient kits recently, and while they've turned out fine so far, the one thing I've noticed is the starting gravity I've recorded is quite a bit lower than the instructions indicate it should be. For example, this weekend, I did a True Brew Bock - 6.6 lbs LME, 1 lb steeping grains. I followed the instructions, but ended up at a 1.042, whereas the instructions said I should have hit 1.050 - 1.052.

I suspect I may be watering the wort down, but I always end up with 5 gallons in the primary (even though I start with a two gallon boil and then add three gallons of water and a little more to make up for the H2O that boiled off). I always use spring water I get from a local store, and while the wort temp may be off a bit, even adjusting for the temperature differential, the S.G. is low.

It's probably not a big deal, but I'm curious to know why I can't seem to hit the mark...any ideas?

 

[Revvy]

Are you sure you're thoroughly mixing the extract water with the water in the primary? I learned that lesson in the beginning. If you're going to agitate anyway do that before taking your reading.

Also another thing, my nephew who has won competitions and is the brewmaster of his club suggested to me to start diluting to your target gravity. Starting w/2 gallons of water in your primary, adding the 2 gallons from your pot. Then taking repeated readings, slowly add the last gallon of water in increments until you hit your target SG. You may end up a couple quarts shy of 5 gallons (or conceivably over 5 gallons if you need more water) But you'll be right in the target.

If a recipe shows a range for an SG, then I aim for squarely in the middle of it.

 

[TheJadedDog]

+1 on things not being properly mixed. When you add your top-off water the heavier wort will sink to the bottom of the fermenter. If you then take your reading from the top, your SG will appear low.

 

[eschatz]

these guys have the answers! haha also, if you want to more accurately hit your target gravity then look at the equations in Designing Great Beers. If you dont own this then you're missing out. It will GREATLY improve your beers. no doubt!

 

[Revvy]

+1 on things not being properly mixed. When you add your top-off water the heavier wort will sink to the bottom of the fermenter. If you then take your reading from the top, your SG will appear low.

It's easier to see in darker beers that you're not mixed when you hold up your theif/hydrometer up to the light. You can almost see the shading difference from top to bottom.

 

[Moonpile]

When we were doing extract we were boiling about 3.5 gals. We'd chill the concentrated wort and then take a gravity reading. Then we'd use the Dilution Calculator in ProMash to figure out how much to add. Never more than a point or two off that way.

Also +1 to making sure it's mixed up first.

 

[Revvy]

When we were doing extract we were boiling about 3.5 gals. We'd chill the concentrated wort and then take a gravity reading. Then we'd use the Dilution Calculator in ProMash to figure out how much to add. Never more than a point or two off that way.

Also +1 to making sure it's mixed up first.

*smacks forehead* That's what I was trying to remember today for another thread...It's called the "Dilution Calculator." Geez I'm gettin old.

 

[TinmanDan]

Thanks for the info, everyone. I had a previous beer where improper mixing could have been the problem (since I took a gravity reading a few days after pitching the yeast, and it was higher than the S.G. I recorded)...however, I don't think that's the case with my latest batch.

Below is a photo of my carboy after I mixed the wort and water. I essentially capped the carboy, picked it up, and shook it like a British nanny (with a nod to Stewie from Family Guy). You can see the resulting foam. In this case, I think I may have just added too much water, but I'll take another reading in a day or so and see what comes.

Or I'll get a copy of Promash and use the dilution calculator. Thanks!

 

[Moonpile]

Check out all the different brewing software. I ended up chooseing ProMash, but you might not. I'm sure they all have dilution calculators.

Brewing software will help you learn more about brewing by allowing you to formulate and play around with recipes and see how things are interrelated.