Taking the OG

[jayhuff]

Today I am in the process of my first AG batch and I have a question...

Can I take a sample right after I combine the mash and sparge together, cool the sample down and get an acurate SG reading? I think it might be too low because of having to boil off extra water. Is that correct?

I am asking because I did this and got a reading of 1.036 and it should be 1.069! If I missed it that much I want to add some DME to get it up there.

My other thought then is to wait till after the boil off and then take a reading. If it is still off I may add DME then.

Any help would be great.
-Jay

 

[BigKahuna]

your o.g. is from the wort just before it goes into the fermentor..after the boil.

 

[jayhuff]

thanks BK! Now if it is too low, would you pump it up with DME or just let it go as a learning experience and see how it turns out? Still would be good I am sure.

 

[modenacart]

It is a very good idea to take a gravity reading, volume and temperature in the kettle before you boil. It will be much less than your OG because you still need to boil off water but you can get an estimate for about what it will be when you do boil off. If the reading you get in your kettle is less than you need you can add malt extract or if it is too much, you can not boil down as much. I have a spreadsheed I am working on that is based off what Ray Daniel's equations. If you PM me I can email it to you. It is still a work in progress.

 

[malkore]

I personally choose to live with the efficiency I end up with. Usually its close enough that my beer is still within style guidelines..

If I was way way low and way outta style, yeah I might add some DME. You could indeed take some wort, cool it, and take the pre-boil OG. Do some math and you can tell if that pre-boil gravity indicates trouble, so you could add a little xtra light DME at 10 minutes to the end of the boil so its sanitary, but doesn't darken up the beer.

 

[jayhuff]

exactly what I did Malkore. Turned out great! It is fermenting away as we speak! No worries now!

 

[modenacart]

I personally choose to live with the efficiency I end up with. Usually its close enough that my beer is still within style guidelines..

If I was way way low and way outta style, yeah I might add some DME. You could indeed take some wort, cool it, and take the pre-boil OG. Do some math and you can tell if that pre-boil gravity indicates trouble, so you could add a little xtra light DME at 10 minutes to the end of the boil so its sanitary, but doesn't darken up the beer.

I don't cool mine when I take the pre-boil OG, I just take it at the temperature then correct it to 60 F. Its close enough for me. I will then put it in the fridge to get a better number if I think about it or just add it back to the boil pot. I really like to do the pre-boil OG because it lets me know where I am when I am trying something new, water corrections or an acid rest or something like that. It only takes a couple of minutes so its not much trouble at all. Besides, I am not doing much when its boiling anyway since I have done most of my work when I am mashing.