Pre boil gravity matters?

[ndhowlett]

Does your pre boil gravity matter? I'm referring to the wort after you've sparged for an all-grain beer. Just don't want to miss anything in the all-grain process.

 

[bradsul]

Checking your pre-boil gravity will let you know ahead of time if you need to sparge a little more or if you need to add some extract to hit your gravity. There's probably a bunch of other reasons but I'm too far gone to think of any.

Personally I don't bother checking mine, my setup is dialed in nicely so it's just not necessary for me.

 

[jdoiv]

If you fly sparge, check the gravity as it is coming out of the MLT every 15 minutes or so. Pay close attention to it at the end of the sparge process as you don't want it to go below 1.008. Below this you are extracting tannins. If batch sparging, taking a pre-boil reading will let you know what your efficiency is, as Bradsul mentioned. You can then adjust either the gravity by adding extract or you can adjust your hops.

 

[azmtnbiker]

I like checking it so I know if I need to boil longer then planned to reach my OG. Also, like the others have said to see if I need to sparge a little more to compensate for the longer boil.

 

[PNWgirl]

Agreed with the others. Just remember to adjust your reading for temperature as that wort will be pretty hot.

 

[Brew-boy]

I check every time during and at the end of sparging. I want to know if I hit my numbers according to Beer Tools Pro. I have my system dialed in pretty good at 83% efficiency but I always want to log my numbers for reference.

 

[zoebisch01]

If you are just getting started and haven't made the recipe in question on your equipment then you'd be wise to take pre-boil gravity. The reason for this is it will affect your hops utilization....so...if your recipe shows x IBU at y gravity, and you get a higher or lower extraction, the time to correct for the hop bittering is pre-boil. Usually it won't make that much of a difference, and yeah it's kind of splitting hairs...but hey if you can, why not? I still take it anyway, well because it's not that big of a deal. I suppose when I have gotten to the point that I have remade a particular recipe a dozen times or so without any changes to my setup I'd probably not bother at that point.

 

[sittingcow]

Agreed with the others. Just remember to adjust your reading for temperature as that wort will be pretty hot.

You can cool a sample in no time by swishing it around in a shallow metal pan.

 

[bradsul]

You can cool a sample in no time by swishing it around in a shallow metal pan.

Indeed you SHOULD cool the sample. The farther from the calibration temperature the less accurate the hydrometer is.

 

[Bobby_M]

For now, suffice to say that checking preboil gravity and recording that number is a good practice on at least your first few batches. It will help you troubleshoot any efficiency issue you might have. Don't forget to stir your wort well first, and make sure you also accurately record the volume (how much preboil wort) you have.

 

[PNWgirl]

Indeed you SHOULD cool the sample. The farther from the calibration temperature the less accurate the hydrometer is.

Yeah I definitely cool it, but I still take the temp into account. I use a calculator at http://leebrewery.com/beermath.htm

 

[raceskier]

I always check pre-boil as a measure of my mash efficiency. Other factors such as boil time and wort loss to a large hop load are more difficult to back out and can mask what you've done in the mash.

 

[zoebisch01]

Yeah I definitely cool it, but I still take the temp into account. I use a calculator at http://leebrewery.com/beermath.htm

The thing to keep in mind when correcting, is the accuracy with the measurement is even more important at high temperatures. So if your gravity point measurement is off by 1 it will change your results more at say 180 °F than at 100 °F.

 

[enohcs]

For the third time today..."Designing Great Beers" Ray Daniels.
It will change your brewing life.
Cheers