Author Topic: All The Variables  (Read 595 times)

Offline jlevensailor

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All The Variables
« on: January 25, 2015, 02:16:17 AM »
So I followed a recipe from a brewmaster friend for a 5 gallon batch of IPA.

I ended up getting high 80's attenuation, but my yield was only about 3/4 of what it should have been and my ABV was a whole percent below his. If I used the same amount of grains, what other variables could be the cause of this? should i be stirring the mash and not just letting it rest? please list all you can think of below:

ie
-strike water temperature
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Offline HoosierBrew

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Re: All The Variables
« Reply #1 on: January 25, 2015, 02:35:53 AM »
 Your volumes are obviously off substantially. You need to be accurate with grain absorption, dead space, and boil off rate for your kettle. Ideally you want to collect exactly the amount of wort that after absorption and dead space losses will leave you with your target fermenter volume plus the amount of evaporation in your boiling period. As for being 1% low on abv, you're not getting the same efficiency as your friend, ie., you're not extracting the same % of sugar from the same malt bill. Figure your efficiency on this batch using beer software and you'll be able to adjust your grain bill to hit your target next time. And BTW, I stir my mash thoroughly to get a steady temp (my target mash temp), close the cooler lid, and leave lone for the mash period. Also, hops will absorb a fair amount of wort on big IPAs, but not 1/4 of your yield.

EDIT -  I think it's a combination of all the above, but all are easily fixable. Good luck.
« Last Edit: January 25, 2015, 03:00:40 AM by HoosierBrew »
Jon H.

Offline tonyccopeland

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Re: All The Variables
« Reply #2 on: January 25, 2015, 02:38:39 AM »
I think we'll need a few more details on the recipe and your process, but on my first big IPA I lost a gallon+ to hops soaking up my wort I didn't expect.
-Tony

Offline jlevensailor

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Re: All The Variables
« Reply #3 on: January 25, 2015, 03:09:51 PM »
OK well i'll ask differently. we used the same amount of fermentals but his is 8.2% and mine is 7.1%
I know lower temperatures of mashing is one variable. I didn't know about stirring your mash, i did not do that.
just wondering how to "squeeze" all the sugar out of my grains
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Offline Stevie

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All The Variables
« Reply #4 on: January 25, 2015, 03:18:19 PM »
Bad crush? Your buddy may get an awesome crush? Incorrect volumes of water? In correct mash pH? In correct mash time? Dough balls?

You don't need to stir the mash during the rest. I do give a stir when I mash in, before I batch sparge, and when I infuse more water.

Sometimes one can't repeat results on two systems off the bat. Might need to learn the little quirks of your equipment before you can effectively replicate a recipe.

What were your volumes? Pre-boil and post

What were your specific gravity numbers? Pre-boil, OG and FG

What was the recipe and the expected OG and FG?
If you don't want to share, give a weight of base malt and a separate weight for specially malts.
« Last Edit: January 25, 2015, 03:22:35 PM by Steve in TX »

Offline reverseapachemaster

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Re: All The Variables
« Reply #5 on: January 25, 2015, 03:55:38 PM »
please list all you can think of below:

Nobody is going to sit down and write an essay for you of all the problems one may have with a mash. There are books well-suited to address that broad question. If you have specific issues with this specific recipe or brew then you would be better suited to offer some information that will allow us to help answer this more specific question. Otherwise I would suggest taking a look at a book like How to Brew or Gordon Strong's book.
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Offline jlevensailor

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Re: All The Variables
« Reply #6 on: January 25, 2015, 04:15:33 PM »
Pre-fermentation my OG was .10 less than his using the same grain bill.
This is basically sugar extraction.

My question was very specific and some of the answers I've received were very helpful. I am going to stir while striking and sparging from now on, for instance.
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Offline hopfenundmalz

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Re: All The Variables
« Reply #7 on: January 25, 2015, 05:07:08 PM »
There are techniques that you need to get repeatable. As said, dough balls limit the sugar, break those up. Stir it well at the beginning to have a uniform well mixed mash and even temperature. Measure and pay attention to the weights and volumes. Get to know your system, and minimize dead space. Temperature is important, is you thermometer calibrated. pH will hurt efficiency if you are too far off. Conversion efficiency can be checked, as if that is not close to 100% you are behind before you ever start the sparge.

Is your system the same as your friends? Even large breweries will get different inefficiencies when they put in a bigger system and compare to the old one.
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