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Author Topic: Poor mash extraction / low pre-boil gravity  (Read 4066 times)

Offline JD5055

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Re: Poor mash extraction / low pre-boil gravity
« Reply #15 on: April 20, 2019, 12:29:02 pm »
I know its already been been said. I've had the same LHBS mill experience. I have switched to BIAB and the first batch I did had awful efficiency 60%+/-. The second time around I ran it through twice and brought my efficiency up 10 points. I bought my own mill and roll as fine it will go and my efficiency is over 80%. Better than when I batch sparged! I now go and buy grain for several batches in one trip and mill as needed. Another savings

Offline kennedmh

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Re: Poor mash extraction / low pre-boil gravity
« Reply #16 on: April 21, 2019, 03:20:36 pm »
So doing the pre-boil and brewhouse efficiency calcs on this most recent brew, I get a mash efficiency (which I think is synonymous with pre-boil efficiency) of 67% and a brewhouse efficiency of 49%.  Not good I'd wager.

Running the same calcs on another recent beer I mentioned that I'd argue went well, I had a mash efficiency of 72% and a brewhouse efficiency of 63%. 

Both brews used grains that my LHBS crushed for me.  Next time I brew, as an experiment, I'll ask them to double crush it.

Other than the gravity readings, my volume measurements are really guesstimates since my brew kettle is an Al one that doesn't have volume markings on it.

Once again, I"m left to shruggie.  Maybe My mash pH isn't what I hope it would be. 

Offline Robert

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Re: Poor mash extraction / low pre-boil gravity
« Reply #17 on: April 21, 2019, 03:26:58 pm »
Don't guesstimate volumes.   Make a dipstick.  You can use the handle of your stirring spoon, a piece of PVC pipe (my preference,)  whatever you want.   Add, incrementally,  measured amounts of water to your kettle, and mark off your dipstick with a Sharpie or the like.   It will be one of the most valuable tools you own! 
Rob Stein
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Offline denny

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Re: Poor mash extraction / low pre-boil gravity
« Reply #18 on: April 21, 2019, 05:38:39 pm »
Don't guesstimate volumes.   Make a dipstick.  You can use the handle of your stirring spoon, a piece of PVC pipe (my preference,)  whatever you want.   Add, incrementally,  measured amounts of water to your kettle, and mark off your dipstick with a Sharpie or the like.   It will be one of the most valuable tools you own!

I'm not a chemist,  but I usually hear CPVC recommended for hot side use.  Anybody know for sure?
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Offline Robert

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Re: Poor mash extraction / low pre-boil gravity
« Reply #19 on: April 21, 2019, 05:53:34 pm »
Not a chemist either, but... yeah CPVC is intended for running hot water lines (up to 180°F IIRC.)   But a) I only dip it in to measure liquor before heating and the chilled wort, so it's not hot.  And b) if I was dipping PVC into hot liquid, I can't imagine it would be there long enough for anything awful to happen.   I used to have a CPVC dipstick.  For a long time it's been PVC.   I have at times used it in hot wort.  I'm still ok.  If you want to be paranoid about something,  I'd go with the Sharpie marks...  ;D
Rob Stein
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Offline denny

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Re: Poor mash extraction / low pre-boil gravity
« Reply #20 on: April 22, 2019, 07:32:17 am »
Not a chemist either, but... yeah CPVC is intended for running hot water lines (up to 180°F IIRC.)   But a) I only dip it in to measure liquor before heating and the chilled wort, so it's not hot.  And b) if I was dipping PVC into hot liquid, I can't imagine it would be there long enough for anything awful to happen.   I used to have a CPVC dipstick.  For a long time it's been PVC.   I have at times used it in hot wort.  I'm still ok.  If you want to be paranoid about something,  I'd go with the Sharpie marks...  ;D

I totally agree with your pragmatism!  Just pointing out a detail for those who might use it differently.
Life begins at 60.....1.060, that is!

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Offline Visor

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Re: Poor mash extraction / low pre-boil gravity
« Reply #21 on: April 22, 2019, 09:50:03 am »
   My experience with Sharpie or pen markings on wood is that they quickly bleed out into useless smudges, unless sealed with urethane. I've made a couple story poles for different brew kettles, both sealed with clear urethane, and have found no ill effects from the sealer, just be sure to let it fully dry for a few days before dunking it in your wort .
   A couple of inexpensive items that have become indispensable around my brewhouse [and kitchen as well] are 1/2 and 1 gallon measuring cups that can be found on Amazon and some of the online HBS.
   As Robert said, don't guess at your volumes!
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Offline ynotbrusum

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Re: Poor mash extraction / low pre-boil gravity
« Reply #22 on: April 22, 2019, 01:58:05 pm »
Similar to Robert, but my dipstick is a HDPE mash paddle with gallon increments from 8 to 15, which is the range I typically make (10 gallons net after fermentation, typically, but an occasional 5 gallon net batch):

It is labeled as food grade:

https://www.homebrewing.org/24-Plastic-Paddle_p_2833.html

Cheers!

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Offline kennedmh

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Re: Poor mash extraction / low pre-boil gravity
« Reply #23 on: April 22, 2019, 02:58:58 pm »
I should say, I'm not guesstimating volumes when it comes to mash water, wether it's strike water, additional infusions or sparge water.  But I don't measure my runnings to the kettle.  I had an HDPE mash paddle that I had marked with sharpie at one time but that only took a few brews for the sharpie to come off, which turned me off because I didn't want to make Sharpiebrau. 

But you all raise a good point.  I think I'll go to Home Depot next time I brew and get an aluminum or steel rod, and file gallon markings into it.  That should be food safe, right?

Offline Robert

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Re: Poor mash extraction / low pre-boil gravity
« Reply #24 on: April 22, 2019, 03:05:01 pm »
I should say, I'm not guesstimating volumes when it comes to mash water, wether it's strike water, additional infusions or sparge water.  But I don't measure my runnings to the kettle.  I had an HDPE mash paddle that I had marked with sharpie at one time but that only took a few brews for the sharpie to come off, which turned me off because I didn't want to make Sharpiebrau. 

But you all raise a good point.  I think I'll go to Home Depot next time I brew and get an aluminum or steel rod, and file gallon markings into it.  That should be food safe, right?
I've never had trouble with Sharpie coming off my PVC.   But I have often thought of doing just what you're talking about.  Just too lazy I guess.   I'd go with the aluminum,  Home Depot isn't going to have any stainless bar stock.  Good move.
Rob Stein
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Offline BrewBama

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Re: Poor mash extraction / low pre-boil gravity
« Reply #25 on: April 22, 2019, 03:29:09 pm »
I used to use a wooden dowel with notches cut into it to mark gallons.  I was glad to move on to an etched kettle. If I end up between gallon marks I know they are 1.5” apart so I use a tape measure to get my qtr and half gallon guesstimates.


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Offline Robert

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Re: Poor mash extraction / low pre-boil gravity
« Reply #26 on: April 22, 2019, 03:36:29 pm »
This baby took some effort, but I'm proud of it.  Quart markings.  Who needs an etched kettle?  :)
Rob Stein
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Offline goose

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Re: Poor mash extraction / low pre-boil gravity
« Reply #27 on: April 23, 2019, 07:18:59 am »
   My experience with Sharpie or pen markings on wood is that they quickly bleed out into useless smudges, unless sealed with urethane. I've made a couple story poles for different brew kettles, both sealed with clear urethane, and have found no ill effects from the sealer, just be sure to let it fully dry for a few days before dunking it in your wort .
   A couple of inexpensive items that have become indispensable around my brewhouse [and kitchen as well] are 1/2 and 1 gallon measuring cups that can be found on Amazon and some of the online HBS.
   As Robert said, don't guess at your volumes!

Just be careful sealing with urethane.  It too can come off in time and put some nasty stuff into your beer.
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Offline kennedmh

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Re: Poor mash extraction / low pre-boil gravity
« Reply #28 on: April 24, 2019, 11:22:07 am »
My old 7.5gal kettle has volume markings in it but I don't think they are very accurate.  I measure my mash water with a pyrex 2qt measure and those embossed markings are off by at least half a gallon.  I realized that a few years ago that I was mashing with more water than I thought and whoo boy was I right.  I don't trust kettle markings but maybe better brands than the LHBS cheapo kettle are more accurate.

Offline KellerBrauer

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Re: Poor mash extraction / low pre-boil gravity
« Reply #29 on: April 28, 2019, 06:09:40 am »
I have also marked my plastic stir spoon with volume graduations based on my boil kettle.  I used a file to mark the graduations and highlighted them with a sharpie with no ill effects.

Back on BeerSmith - BS uses to entries to calculate mash efficiency. 1) Pre-boil Gravity and 2) Pre-boil Volume.  So, by increasing (or decreasing) either one of these numbers will dramatically change the mash efficiency presented in BS.  So, in my opinion, you first need to dial in your Equipment Profile within BS.  That said, a good grain crush, as the other brewers have pointed out, is vitally important.  However, in BS, if the software thinks you have a 75% efficient BrewHouse, then it will project all your SG’s based on that factor.  So, if your BrewHouse efficiency is, in reality, actually more like 65%, than all the numbers start to collapse, starting with the Mash efficiency since that’s the first real measure of efficiency the software presents.

So, assuming the grain crush is perfect, if your Equipment Profile within BS is not accurate, neither will the projections and estimates.
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