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Beer Baron

Grain Values Changing

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Hi everyone. 

I made a recipe last year and it came out at 6.4%. I entered the exact same recipe today for a batch that I am going to brew soon and the ABV is 5.9%. 

Does the grain value change annually?? 

Do I need to increase my grain at the same percentages to make the exact same beer?? 

Thoughts??

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I recently had the same issue. 

With all agricultural materials, it will change harvest to harvest. Then the maltser will have a go and that could be slightly different from batch to batch too, then your mill size might be slightly different and therefore your efficiency is out. I adjusted my water amount slightly and got my efficiency back to where it should be. 

Could also be your mash temp, maybe higher? Accounting for less fermentable sugars. 

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different yeast, different volume?

where did you enter said stuff?

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Sounds like a case of the brewing of the recipe not quite matching the software prediction? Happens all the time for me although usually not that much difference. Maybe comes out 0.1-0.2% different to the prediction.

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ABV variation depends on a lot of things. Even the big breweries have a 0.5% ABV margin i believe as it is inherantly variable.

For example I have a belgian dark strong beer cold crashing at the moment where the OG was 1076. Was supposed to finish at 1010 ish like the last one but for some reason the yeast took it all the way to 1002. 9.1% ABV in the bottle it should have been but actual will be 10.2%. Same recipe. Same yeast. Same ferment schedule. The last one OG was 1078 to 1010 and this one 1076 to 1002.

Wyeast also says 74 to 78 attenuation on this yeast as well. Its never been below mid 80s and this one was 97%. There attenuation numbers especially for belgian strains aint worth squat..

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EXACTLY the same including batch, yeast and mash temps. 

I use the Grainfather app

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Are you saying the software predictions were different each time you plugged the recipe in, or that the 6.4% one was an actual measured figure from brewing and fermenting the batch? The latter would make sense, your OG may have been higher than the software prediction when you brewed it or the FG lower than the prediction. Was it bottled or kegged and does the app account for the ABV contributed by priming sugar?

Software won't automatically change grain specs, you have to do it manually unless the grain father app is different like that. However, while the grains do vary slightly from season to season, I doubt they'd vary enough to change the ABV by that much. 

The first all grain lager I brewed turned out 1% higher in ABV than beersmith suggested when I constructed the recipe. The reason being the efficiency was still set to the default 70%, as I hadn't really measured my actual efficiency yet. Obviously the real life figure was higher. I changed it for the next batch and it came out on target.

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I made the recipe twice last year and it was predicted to be 6.4% and it came out at 6.4%. 

This time when I enter it’s predicted at 5.9% and I am 100% sure I have the exact same recipe. 

My efficiency is 75% and I’m always pretty much at that target.

I only keg so no priming is required.

 

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You must have done something different, left out a grain or added less base malt or something. It shouldn't change if it was entered the same.

Every time I make a pale ale I put the same grist, mash temp and yeast in and get the same predicted OG, FG and ABV. 

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I log each brew and I’m 100% sure it’s the same. There is a copy brew tab

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Do you have any screenshots of each one? Maybe one of us can spot a difference.

Edited by Otto Von Blotto

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This is the first batch and was originally predicted at 6.4% and came out at 6.4%

822A53F3-F73F-4C17-8D3F-12E416207C15.jpeg

E4BF1625-FACB-4AA2-85B9-D9E467CEAF09.jpeg

943A1B17-E770-448E-87F7-97558C42B8D3.jpeg

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I can't see any difference between the two in those pictures. Were you still bottling when you first brewed it? Or is there a bottle carbonation option on the app that may have been selected for the ones that it predicted higher ABV?

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No boil off rate or pre boil gravity listed and I have always kegged since going all grain

Edited by Beer Baron

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Well buggered if I know then. Brew it as you always have and see if it comes out at 6.4% again. 

The only other thing I can think of is if there was an update to the app that may have changed the way it calculates ABV.

What is the OG and FG of the recipe?

Edited by Otto Von Blotto

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I am absolutely lost too. 

I’ll just brew it soon and see what numbers I get. 

OG 1.054

FG 1.010

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Using the formula I run with it comes out about 5.8% from those figures. Not sure where they're getting 6.4 from

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14 minutes ago, Otto Von Blotto said:

Using the formula I run with it comes out about 5.8% from those figures. Not sure where they're getting 6.4 from

Maybe it was wrong all along........but why did I get 6.4% when I brewed the other times😕

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Maybe your real life OG and FG were different from what the app predicted. That would be the only way it could be different. 

There are a few different formulae for calculating ABV but they usually only differ by 0.1% or so.

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