How much would SG drop after first day?

[phlippieb]

Hi!

A colleague and I recently brewed some beer. Sadly, our hydrometer broke before we could read the OG, and since it was Sunday night, we couldn't get a new one until the next afternoon. We could only measure it about 20h later.

We're brewing 150l (!) Australian Pale Ale. We used six LME kits of Mangrove Jack's Australian Pale Ale (https://mangrovejacks.com/products/australian-pale-ale-with-dry-hops) along with 6 x 1.2kg pure malt enhancers. From a bit of searching around, I guess our OG should have been about 1.04 to give us about 4.5% ABV. When we measured it 20h after brewing, SG was only 1.031.

The room temp would have been at around 20-25*C on average, and by the time we measured SG, we could smell that fermentation was coming along nicely.

We're worried that we may have added too much water (6 kits * 23 liters < 150 liters), and that our OG would have been too low, but since we couldn't measure OG, we have no idea. How much do you guys reckon SG would drop after the first day? Could it actually be a whole 0.01?

 

[doug293cz]

SG can definitely drop 0.010 in a day of active fermentation.

When brewing with extracts, you almost don't need to measure the OG if you have accurate volume measurements. Knowing the volumes and sugar content of the extracts you can calculate the OG to very good accuracy. (Often the calculations are actually more accurate than the measurements, due to some common mistakes in measuring SG.)

Brew on

 

[phlippieb]

Ah cool, good to know! We have this big ol' 180L fermenter that isn't calibrated, so we were actually planning to rely on SG as the more accurate measure of how we're doing, but you make some good points on that. If I trust the measurements, though, we have about 12L too much water in there.

Is it generally not advised to add some malty/sugary solution to the fermenter after fermentation started?

 

[doug293cz]

...

Is it generally not advised to add some malty/sugary solution to the fermenter after fermentation started?

I have heard of it being done, particularly for high alcohol brews, in order to not overload the yeast with sugar initially. I don't see why adding sugar would be a problem, you just need to be sure that the sugar solution you add is much more concentrated than your original wort, otherwise you are mostly increasing the volume, but not the effective OG. But, I have never done this, so don't base a decision solely on my advice.

Brew on

 

[jrgtr42]

Unfortunately, there's no way to know - SG can drop either not at all, or most of the way down to FG in a day, depending on, oh, a million things.
About the adding in later, like Doug said, it's been done, but for something like what you have, it's probably not ideal.
You can probably get pretty close to your SG by entering your info into one of the Brew calculators, I use BrewToad, Brew Mate is another, there's lots of them out there. Especially being extract, as long as you know the amount of liquid you added to your extracts, you'll be pretty close to your actual SG.

 

[phlippieb]

Cool. Thanks for the answers folks!

 

[BlueHouseBrewhaus]

If you added 12L too much water, you could figure out how much extract (or just sugar) in 12L will give you 1.040. Give it a 10 min boil and add it to the fermenter. It will kick off a second round of fermentation and raise your effective OG without changing the flavor noticeably.