Consistently 1 to1.5 gallons more in Pre-boil. Why?

I have no idea why this is occuring but I am consistently achieving a gallon to a gallon and a half more wort for the pre-boil. My pre-boil gravity for the last brew was way off 1.036 instead of 1.056 for a mash efficiency 62.7%. I was supposed to have 7.69 gallons according to BeerSmith and ended up with 8.5 I have re-calibrated the sight glass it was off slightly before this brew.

In the past I have ended up with as much as a 1 3/4 gallons extra but my efficiency was much higher (82.7%).

I generally don't mind having more wort (I typically boil off 2 gallons per hour) and come close to the post boil gravity, however, with the lack of efficiency this time and the increase amount of wort, I am becoming concerned there is a larger problem occuring in my brewing process.

Any ideas why this is happening and what I can do to address this problem? Should I be concerned?

Thanks!

...also for the last brew I did one large sparge of 6.24 gallons instead of two smaller ones. I think I read somewhere it will produce a smoother beer (this is a sweet stout). This is the first time I have done this.

Thanks again.

How many times has this happened, twice? Not sure exactly, but my guess is a number of things:

Your settings in BeerSmith may need to be adjusted to account for your set-up
You're sparging with too much water
You're running off more volume than you need

I'll occasionally have liquid left in my mashtun after I'm done lautering. We draw that off to make a small beer in a separate brew kettle.

I always have some water left in my mash tun. I just shut off the sparge and spigot from mash to boil when I get the volume I want. Every system is a little different - you need to account for the way your system works.

In addition to whatever beersmith might be telling you, I would also advise measuring the amount of runnings produced, and in the kettle prior to your last sparge, the wort needed to reach your preboil volume will be your last sparge amount...KISS principle and also a confirmation of what the software should be telling you...brewing software can be a great tool, but keeping your eyes open and having a hands on grasp of the basic concepts goes a long ways IMHO.

Sorry, but no idea why your gravities are amiss.

Thanks for the responses. This (extra wort) has happened for several brews (four or five probably more). I believe the efficiency is probably off due to the one sparge method and am thinking of changing the "Tun Deadspace" in BeerSmith as it is set to .80. I put a gallon of water in my mash tun and had 12 oz of water at best of water left. Not a math whiz, I don't believe that is necessarily 80 percent of a gallon...I need to do some math...

On my first ag i set the tun dead space to 0 and set pre boil to 6.5. I mashed 16.5 qt for 12.5lb of grain and got back 2.5 g but i also tipped my tun to about 45 degree to make sure i got that. than sparged with 4.2 gal and got back the 4 i needed to to hit my pre boil. while i was boiling i let my tun trickle drain and had a little less then a qt sitting there when i was finished boiling. my post boil was 5.4g being my first i figured i "reverse engineer" the process to see how my system worked.

Mash tun dead space would be a very good place to start. The thing with the dead space is once it's full of liquid, it's full. If you measure how much water you mashed-in with, and how much you've colleced with your first runnings, the difference is your dead space. After the initial run-off, the dead-space is full of liquid so any additional batch sparges should yield the same amount of liquid in and out regardless of your dead space.

annoyingrob said:

If you measure how much water you mashed-in with, and how much you've colleced with your first runnings, the difference is your dead space.

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Sorry to be annoying rob....hahah

...but the difference would be your dead space plus grain absorbtion.

Are you batch sparging? (It sounds like you are).

If so, there is a very easy fix. Mash as usual, and then measure the first runnings. Then you'll know exactly your grainbed absorption and your dead space. Subtract the amount of your first runnings from the desired boil volume, and then sparge with that amount (and one round of the full amount is fine).

Then, tweak all of your Beersmith settings to your actual results. We can help you with that.

After that, you should be dead-on with Beersmith.

wilserbrewer said:

Sorry to be annoying rob....hahah

...but the difference would be your dead space plus grain absorbtion.

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d'oh!

You're right, I forgot about that part :cross:

Is this right: First runnings-second runnings (of the same exact amount)= deadspace and grain absorbtion

So for my last brew I had approx. 2 gallons from the first runnings would I then pour that 2 gallons from the first runnings (I mashed in with ~3.63 gallons) back into the mash tun or leave it in the boil kettle?

DPB said:

Is this right: First runnings-second runnings (of the same exact amount)= deadspace and grain absorbtion

So for my last brew I had approx. 2 gallons from the first runnings would I then pour that 2 gallons from the first runnings (I mashed in with ~3.63 gallons) back into the mash tun or leave it in the boil kettle?

Click to expand...

You put your first runnings in the boil kettle. Then you add your sparge water to the mashtun and stir well, and drain.

When you measure your first runnings, you'll know exactly how much sparge water you need (as the MLT and grainbed won't absorb or lose any more). So, if you pull out 2 gallons from the MLT as first runnings, and you want to have 6 gallons preboil volume, you know you need 4 gallons of sparge water.

Thank you! It sounds easy enough. I'm brewing next week will report back with the numbers.

Deadspace and absorption are the only two places water can go. So yes, measure first runnings, subtract strike water, subtract your known deadspace, that's your absorption. divide by the weight of grain to get rate.

I love using beersmith. But I've never bothered with its offerings post the mash in. I batch sparge and collect my first runnings subtract it from the total I want and off I go. Software is great but sometimes we need to remember whose the brewer, Beersmith or you?