OG is always higher than expected. Why?

[osoling]

This might be an odd thing to complain about, but I'm doing something in my brew day that is causing my sort to have a higher specific gravity than expected.

I've just started brewing Brew-in-a-bag, but I had the same issue when I was brewing extract.

For example, yesterday, I brewed an IPA. I was looking for 1.050 but I got 1.064. My last few batches have been higher in alcohol than the target. And I'm trying to brew smaller beers. 50 bottles of 11% is a lot of big beer to drink.

So, what can I do in my brew day that would cause the sg to go up? How am I messing up? Theories?

Thanks for your help.
Osoling

 

[photobru]

What are your volumes (mash, pre-boil, after boil, and then at pitching)?

 

[McKnuckle]

The most common reasons for higher than expected OG include:

1) Higher mash efficiency than estimated - you got more sugars out of the grain during the mash; or
2) More evaporation than anticipated - you reduced wort volume during the boil and concentrated the sugars

 

[beergolf]

Are you doing partial boils and adding top off water?

IF so then you probably are taking a reading from wort that is not fully mixed with the top off water.

 

[Clonefan94]

Is your hydrometer calibrated correctly? My first guess would be that it could be giving you false readings.

My second guess would be that your volumes are off. How do you know you have 5 gallons? If you are going off of pre printed markings on a bucket or kettle, double check those. It's rare that those are that accurate.

As others have said, partial boils can be an issue with getting all the sugars mixed. I have tested this theory myself and have in fact gotten 3 different readings from the same wort, based on when and where I pulled the sample from.

 

[jbob7171]

For your batch yesterday, you say you were expecting 1.050... what efficiency were you using to get this estimate?

As far as extract batches, if use the correct amount of LME or DME the recipe calls for and have the correct volume into your fermenter, you can be assured your OG is where it should be, even if the reading is off. Probably a case of not mixing your wort and top-off water well enough before sampling.

 

[osoling]

Thanks for the answers so far. I started with 6.5 gallons of water. I ended up with just slightly more than 5 gallons. Like 5.1 gallons. I measure by the notches I made in my brew paddle after adding a gallon, then another gallon, etc. I didn't top up because I got my final volume in the boil.

Because it was brew in a bag, I upped my main grain by a pound to make up for the under-efficiency of the process.

What else can I answer for you? This is helpful.

 

[TheHopfather]

Upping the grain will give you more sugar, I think you just answered your own question. Do you use brewing software? I'd just start entering your OG and FG readings into the software and it will calculate your efficiency for you. Just adjust your recipes based on your particular efficiency, problem solved.

What makes your efficiency "higher than expected" in the first place? What is your expected efficiency and how did you come by that number?

Edit: I see people regularly reporting 80 - 90% efficiency with BIAB. I'm not sure where this idea comes from that you'll get a lower efficiency vs 3 vessel but I think it is safe to say it isn't true. You just need to worry about YOUR particular efficiency.

 

[frettfreak]

Because it was brew in a bag, I upped my main grain by a pound to make up for the under-efficiency of the process.

What else can I answer for you? This is helpful.

Upping the grain will give you more sugar, I think you just answered your own question. Do you use brewing software? I'd just start entering your OG and FG readings into the software and it will calculate your efficiency for you. Just adjust your recipes based on your particular efficiency, problem solved.

What makes your efficiency "higher than expected" in the first place? What is your expected efficiency and how did you come by that number?

Edit: I see people regularly reporting 80 - 90% efficiency with BIAB. I'm not sure where this idea comes from that you'll get a lower efficiency vs 3 vessel but I think it is safe to say it isn't true. You just need to worry about YOUR particular efficiency.

Hop father is on it! You cant add grain and expect to hit your numbers, you are adding more sugars to the wort. but i think the bigger issue would be where you are getting your numbers and how they are being calculated. IF you use software such as beer smith, then your equipment profile needs to be tweaked a little to match your system and style.

 

[Owly055]

There is a myth that BIAB is low efficiency..... It's not. I've hit some amazing efficiency numbers.... as high as 90% or more, when using a fine grist and sparging the bag. Clearly the additional grain along with a higher than expected efficiency is the "culprit". I use Brewer's Friend, and it defaults to 75% efficiency, and it is rare that I don't exceed the OG numbers by a considerable amount. Efficiencies between 80 and 85% are typical. My typical mash is from 20 to 30 minutes and I get good (expected) attenuation. By simply changing the efficiency field until it matches the OG, it's easy to tell what your efficiency is.

H.W.

 

[McKnuckle]

With a standard single run through the grain mill and no sparge, just lots of stirring and a long gravity drain, I hit 76-85% mash efficiency with BIAB. In fact, for me it's almost always more extraction than I get with a 3 vessel system and either batch or fly sparging.

You need to start analyzing some numbers I think, not just guessing and/or following what other people's recipes state. Everyone's system is a little different.

 

[MuddyCreek]

With small batches and a good crush in your BIAB you CAN hit really great efficiency. If you are consistently hitting that kind of OG then you've got to consider that you're process is providing better efficiency than whatever recipe parameters you're planning for.

Every recipe should have efficiency calculations that let you know how much grain to use for the mash and sparge. Experimentation with your own equipment will tell you over time what YOUR efficiency is and you'll adjust your grain usage accordingly so you can reproduce the same OG time after time. Then with future recipes of different beers you'll know the efficiency that your system produces.

(This is why SMASH (Single Malt and Single Hops if you aren't familiar with the acronym, if you are I'm sorry for being sophomoric.) recipes are so helpful. You get a great idea starting out what your system efficiency is.) Of course, over time as you generally get better, your efficiency will likely improve a bit. But you'll see that and you can adjust your grain ratios accordingly.

So if you're REGULARLY getting .012 to .015 above your expected gravity, it could be that you're just that good. (That's not at all unusual.) The good news is, you get to save some money, use less grain. As suggested above, find a software program that will help you adjust your recipe for efficiency and you should be able to hit your target OG much more reliably.

When you DO go high, your best option is to adjust before pitching yeast with filtered or boiled liquor until you have the right OG and make sure you are evenly mixed. Then cool to pitching temp and pitch your yeast. The problem there is that you'll have MORE wort than you originally planned so you may need to put aside more yeast to ensure a healthy pitch.

There is no problem you can't solve with just a little more beer.

 

[osoling]

This was great information. I added the extra pound because the very helpful guy at the lhbs told me to. My plan was (is) to follow his advice to the letter, see what happens, and adjust.

I think what I learned here is that I don't need the extra pound. The recipe said that it expected 75% efficiency, and I got that, but with an extra pound of grain. I'm ball-parking here, because I also learned that I need to get the actual data, which I will begin working on.

Thanks a lot, you fine folks, for helping me think about this and figuring it out.