Jump to content
Mr.Beer Community
Sign in to follow this  
mnstarzz13

AG Noob Question: Pre-Boil SG

Recommended Posts

I have done a few Ag BIAB batches now and just recentlt, i started to be curious about my efficency.

When one measures their pre boil SG, do you have to let your wort cool in the hydro tube before you take a reading? After my mash on my last batch, I removed grains and drained. The temp was 148 and I took a reading of 1.022. Per Qbrew thats adjusted to 1.041 (IIRCC) But when I used another tool online to calc eff. it said the max temp I could choose to correct my reading was 120 something.

How should i go about this? i imagine at some point he hydrometer will not be accurate....

Share this post


Link to post
Share on other sites

I've never taken a preboil reading, but I do know that you shouldn't use a hydrometer in high temps. It won't just be inaccurate; it can break it.

Share this post


Link to post
Share on other sites

Yeah my understanding is you start getting really far off at those temperatures...I let it cool in the freezer until it's cool to the touch (roughly under body temp).

Share this post


Link to post
Share on other sites

I let mine cool before measuring it. I'll pull a sample of wort out pre-boil and let it cool in a glass while I start the boil. I don't trust putting hot liquid into the relatively cheap plastic the hydro tube is made of. Once its cooled I'll pour it in the tube, take the measure, then add it back into the boil pot.

Share this post


Link to post
Share on other sites

Lurch69 wrote:

I let mine cool before measuring it. I'll pull a sample of wort out pre-boil and let it cool in a glass while I start the boil. I don't trust putting hot liquid into the relatively cheap plastic the hydro tube is made of. Once its cooled I'll pour it in the tube, take the measure, then add it back into the boil pot.

Never thought of that. FWIW, I have the Mr. Beer hydro tube and it hasn't been a problem putting mash-temp wort in it and cooling in there. Easier for me to put in the freezer.

Share this post


Link to post
Share on other sites

SenorPepe wrote:

Lurch69 wrote:

I let mine cool before measuring it. I'll pull a sample of wort out pre-boil and let it cool in a glass while I start the boil. I don't trust putting hot liquid into the relatively cheap plastic the hydro tube is made of. Once its cooled I'll pour it in the tube, take the measure, then add it back into the boil pot.

Never thought of that. FWIW, I have the Mr. Beer hydro tube and it hasn't been a problem putting mash-temp wort in it and cooling in there. Easier for me to put in the freezer.

+1 I wouldn't want to put boiling water in it, but the temperatures at the end of the mash are low enough that it doesn't cause me any concern.

And I do the same thing...I cool the hydro sample before measuring the pre-boil gravity. I like to get it below 100.

Cheers!

Share this post


Link to post
Share on other sites

I take 3 hydrometer readings and record them all before pitching my yeast. The first one I take is at the very start of the lauter, then next one is at the end of the lauter and the third one just prior to pitching my yeast. For the first two readings I put the hydrometer and sample tube into the refrigerator until they cool off before recording the readings.

Share this post


Link to post
Share on other sites

genotype wrote:

If the readings come in lower than expected, do you use extract to bring it up?

this is the next thing I need to nail down. I am sure Beersmith would be needed to know what the preboil OG should be but maybe not if you know your boiloff rate...haven't had time to figure it out. but with my last batch I need to. I shoulda had an OG of 1.046 but my reading was 1.036 so I will have overhopped 3.2 beer. things could be worse i guess.

Thanks for all the replies! I will need to adjust my brew day process to make sure I lower the temp....only issue I'll have is getting a temp. i use a big candy thermometer for mashing and that doesnt fit in my hydro tube so will have to think of something. :cheers:

Share this post


Link to post
Share on other sites

Are you working out your brewhouse (post-boil) efficiency too? Ultimately, that number may be more useful to you for planning your recipes since you may lose a couple of points to wort lost in the hop and protein residue, especially if you siphon as opposed to strain your wort into your fermentor.

FWIW, touching on genotype's comment, I've added a boiled extract solution as much as 24 hours after pitching to bring up the gravity to a desired amount. Haven't had a problem, but I suppose it's safer to do it during your boil if wind up short.

Share this post


Link to post
Share on other sites

I have been tracking preboil sg, preboil volume, post boil volume, post cool down volume, transfer volume and volume left in brew pot. I just am not sure what to do with these numbers yet. Besides knowing how much boil off to expect and shrinkage i dont know how to use the info to my advantage during recipe creation. I spose it is all about working backwards to ensure your transfer volume is spot on....just gotta connect some dots. ;)

Share this post


Link to post
Share on other sites

mnstarzz13 wrote:

I have been tracking preboil sg, preboil volume, post boil volume, post cool down volume, transfer volume and volume left in brew pot. I just am not sure what to do with these numbers yet. Besides knowing how much boil off to expect and shrinkage i dont know how to use the info to my advantage during recipe creation. I spose it is all about working backwards to ensure your transfer volume is spot on....just gotta connect some dots. ;)

Well, all those things can be useful to a point, especially knowing how much boil off to expect, and how much winds up in your fermentor. That way, if you decide to do a two hour boil, you know how much wort to draw from your sparge. Likewise, if you have more wort than you planned for some reason, you know how long to boil it to get it to your desired final amount. Of course if you boil too long, you can always top off with water. Knowing your brewhouse efficiency, based upon the final amount in your fermentor enables you tailor your malt bill. If you know that you are consistently getting a 75% efficiency, and you are trying to duplicate a 6.8% ABV beer, you now have the information you need to to determine how much malt will get you there. Of course, knowing how well your yeast attenuates is important too. Being a lazy man, I don't bother to do the math anymore. I just set my efficiency in the brewing calculator, and it does the rest when I enter in a certain weight of grain.
Just a note of caution. If you switch maltsters, you may get different numbers, which will throw you off for the first couple. For instance, when I use Briess or Rahr malts, I enter an 83% efficiency into the calculator (I use QBrew and Beer Mate). I recently bought a 50 pound bag of Canadian malt, and had to adjust my efficiency to 77%. Unfortunately, I was trying to duplicate recipes with the new malt, and had to add DME to make up the difference when my OG was suddenly lower than expected. It took me four or five beers with the new malt before I was comfortable formulating recipes with it.

Sorry for rambling, hope that wasn't too incoherent.

Share this post


Link to post
Share on other sites

genotype wrote:

....If the readings come in lower than expected, do you use extract to bring it up?

genotype while the thought of adding DME has crossed my mind several times, I'm really ok if I come up a few points short of my targeted original gravity, so far that's all I've been off.

Share this post


Link to post
Share on other sites

Not to get too far off-thread, but since I'm going more and more full-volume AG with my recipes, I'd like to know how to calculate brewhouse efficiency.

For now, it's just for my own curiosity, but I know eventually the light bulb will come on, and I'll see the Bigger Picture and start using it as another factor in planning my recipes, so I'd like to get used to using it and recording it.

Share this post


Link to post
Share on other sites

FedoraDave wrote:

Not to get too far off-thread, but since I'm going more and more full-volume AG with my recipes, I'd like to know how to calculate brewhouse efficiency.

For now, it's just for my own curiosity, but I know eventually the light bulb will come on, and I'll see the Bigger Picture and start using it as another factor in planning my recipes, so I'd like to get used to using it and recording it.

Dave about a month back we covered brewhouse efficiency pretty thoroughly in the Hydrometer Readings And Brewhouse Efficiency post and followup threads. It was one of those topics that triggered a deep dive of the subject by some of the veteran Borg brewers and it'll be a great place for you to start. If you have any questions just post them there and I'm sure someone will pick it up again and reply.

Share this post


Link to post
Share on other sites

Screwy Brewer wrote:

FedoraDave wrote:

Not to get too far off-thread, but since I'm going more and more full-volume AG with my recipes, I'd like to know how to calculate brewhouse efficiency.

For now, it's just for my own curiosity, but I know eventually the light bulb will come on, and I'll see the Bigger Picture and start using it as another factor in planning my recipes, so I'd like to get used to using it and recording it.

Dave about a month back we covered brewhouse efficiency pretty thoroughly in the Hydrometer Readings And Brewhouse Efficiency post and followup threads. It was one of those topics that triggered a deep dive of the subject by some of the veteran Borg brewers and it'll be a great place for you to start. If you have any questions just post them there and I'm sure someone will pick it up again and reply.

Thanks for the link. Definitely check it out as AG/BIAB is where I'm heading full time as well.

Share this post


Link to post
Share on other sites

Excellent! Thanks, Screwy! I'll bookmark it and read it this weekend.

I do recall seeing it, and starting to read it, but it didn't really have much meaning for me at the time, and my eyes started glazing over, and I was even drooling a little, so I think I logged out and watched Animaniacs for a while until I felt better.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...