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O.G. and F.G. too high yet yield the correct difference

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KookyBrewsky

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I recently brewed a BIAB Two Hearted clone... Are differences in efficiency readings going to be expected with BIAB?

For instance, my O.G. was 1.079 and my F.G. was around 1.030, with hydrometer calibration adjustment, difference of 0.049.

The recipe calls for an O.G. of 1.061 and an F.G. of 1.016... Expected difference of 0.045...

Mine is a little stronger but the difference is close enough and what I am wondering about. Does the range shifted up mean I messed up somehow? Is it better, worse, what is the deal? I thought this brew went quite well except for the fact I ended up with around 4.75 gallons due to boil off instead of a little over 5 that I expected.
 

Coastalbrew

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I recently brewed a BIAB Two Hearted clone... Are differences in efficiency readings going to be expected with BIAB?

For instance, my O.G. was 1.079 and my F.G. was around 1.030, with hydrometer calibration adjustment, difference of 0.049.

The recipe calls for an O.G. of 1.061 and an F.G. of 1.016... Expected difference of 0.045...

Mine is a little stronger but the difference is close enough and what I am wondering about. Does the range shifted up mean I messed up somehow? Is it better, worse, what is the deal? I thought this brew went quite well except for the fact I ended up with around 4.75 gallons due to boil off instead of a little over 5 that I expected.
With a higher og, I would expect a higher FG, so I think your fine there. Generally BIAB is sightly less efficiency due to no sparge, but there are lots of people who do get really good efficiency which will push your og up. Also a higher boil off rate will increase your og. So it could be a little of both boil off and efficiency that got your numbers off. It's not a huge deal one way or another. The beer will be a little different than intended is all. Keep good notes on each brew day, compare the stats, and tweak your recipes and process and you'll get your system dialed in pretty quick to get closer to the numbers you want.

You can do a boil off test to figure out your actual boil off rate, as this will vary depending on a variety of factors. I like to track my bh efficiency along with all the other common stats on each brew so I can watch tends and dial in my recipes accordingly.

Cheers!
 

VikeMan

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For instance, my O.G. was 1.079 and my F.G. was around 1.030, with hydrometer calibration adjustment, difference of 0.049.

The recipe calls for an O.G. of 1.061 and an F.G. of 1.016... Expected difference of 0.045...
An OG of 1.061 and an FG of 1.016 is ~74% Apparent Attenuation. I'd expect a bit more attenuation (and thus a lower FG) from a Two Hearted clone, but let's say 74% attenuation is spot on.

An OG of 1.079 and an FG of 1.030 is ~62% Apparent Attenuation, which is way too low for this beer. 74% Apparent Attenuation of a 1.079 OG would have got the FG to ~1.021.

Either the batch was still attenuating (did you take 2 readings 2-3 days apart?) or something caused it to stall.
 

doug293cz

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A 1.030 FG is extremely high. Are you measuring with a hydrometer or refractometer? Once fermentation starts, the alcohol makes the refract readings higher than the actual SG, so you need to use a calculator to correct the reading if you want a reasonable accurate FG reading.

If that's a hydrometer reading, I would suspect that your fermentation has not finished.

Brew on :mug:
 
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KookyBrewsky

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I don’t think I could’ve done anything else besides bottle today, it has been over 3 weeks in primary. There’s a possibility my hydrometer is broken. Upon inspection the inside looks a little weird compared to how I remember it...

Fermentation was extremely busy for many days. I hope the batch isn’t ruined, it’s always something for me!
 

VikeMan

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There’s a possibility my hydrometer is broken. Upon inspection the inside looks a little weird compared to how I remember it...
Test it with water at whatever calibration temp is printed on it, and see if it reads 1.000.
 
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KookyBrewsky

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Test it with water at whatever calibration temp is printed on it, and see if it reads 1.000.
yep it’s roughly 1.000. My last two batches have been questionable. This will probably be the worst by far and the one I was looking forward to most. I’ve never done an all grain IPA before :/
 
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VikeMan

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What was your mash temperature and how did you measure it? And is your thermometer calibrated?
 
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KookyBrewsky

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What was your mash temperature and how did you measure it? And is your thermometer calibrated?
I followed these instructions exactly : https://www.homebrewing.org/assets/images/Recipe_Instructions_2019/ag99-2660.pdf . My mash temp got a little low so I heated the mash one time, other than that I can’t think of any issues the entire time. My temp was definitely never below 149F and never above 156F except when I first put the grains in. I did my best to keep it between 152-154F.

Thermometer during brew is part of my Spike kettle, I guess I will have to check it out though it’s never caused any issues before as far as I can tell.
 

VikeMan

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Thermometer during brew is part of my Spike kettle, I guess I will have to check it out though it’s never caused any issues before as far as I can tell.
I would check that just to be sure. Unintentionally high mash temps seem to be a fairly common cause of less fermentable worts, if indeed low fermentability was the problem.
 

Kickass

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Yeah, that’s a high FG. Two culprits that stand out are yeast and equipment measurement accuracy.

Was your yeast healthy and did you have a proper pitch rate?

Are your thermometers and hydrometer accurate?
 

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I’ve never done an all grain IPA before
My mash temp got a little low so I heated the mash one time, other than that I can’t think of any issues the entire time. My temp was definitely never below 149F and never above 156F except when I first put the grains in. I did my best to keep it between 152-154F.
Any time you try to heat up a mash you need to be stirring constantly and vigorously. If not, the bottom off the mash gets much hotter than the top because the grains restrict the circulation and that can destroy the enzymes that are needed for conversion. Basically you are doing a "mash out" on the bottom portion of the mash. Best solution is to dough in the grains, cover the mash tun and insulate. Don't worry if the temperature drops a little during the hour long mash, conversion might have been over long before that. If not, you will get a wort that can attenuate more than you want. That will tell you that you need to start the mash at a little higher temperature.
 
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KookyBrewsky

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Yeast health seemed fine, I mean it was reharvested yeast after a two stage starter with much help in its preparation from people on here. Activity both during starter and tons during fermentation.

I can recall I had already tested the thermometer it came with in perfectly chilled ice water and it was very accurate. I’ll test again today but unless it’s completely broken it should be just as accurate

I wrap my kettle in a thick blanket, my starting temp may have been a bit low. While heating the mash I was stirring constantly with my paddle.
 
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KookyBrewsky

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Any last ideas?

Thermometer attached to kettle is calibrated, yeast health seemed fine as it showed great activity and went from 1.079 to 1.030, fermentation temperature is controlled, when I reheated my mash one time it was stirred constantly with a paddle, grain was freshly milled relatively fine....

Here’s something I had never done variable wise.. I used Irish moss to try and clear the beer up for the first time. I used recommended amount and it said the last 15 minutes of boil but I ended up having to boil for 30 minutes due to having too much water left and ended up with too much trub in the end anyway.

Going from 1.079 to 1.030 what % will my beer be? The calculation doesn’t work that high up or the attenuation just wasn’t correct for it to work?
 

VikeMan

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Any last ideas?
Unless I missed it, you haven't said if you took a second reading 2-3 days after the last one.

Here’s something I had never done variable wise.. I used Irish moss to try and clear the beer up for the first time. I used recommended amount and it said the last 15 minutes of boil but I ended up having to boil for 30 minutes due to having too much water left and ended up with too much trub in the end anyway.
That shouldn't affect attenuation.

Going from 1.079 to 1.030 what % will my beer be? The calculation doesn’t work that high up or the attenuation just wasn’t correct for it to work?
6.4% ABV if the FG doesn't move. You might want to find a better calculator. Here's a standalone one:
Or, get some brewing software.
 
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KookyBrewsky

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Unless I missed it, you haven't said if you took a second reading 2-3 days after the last one.



That shouldn't affect attenuation.



6.4% ABV if the FG doesn't move. You might want to find a better calculator. Here's a standalone one:
Or, get some brewing software.
Sorry if my question was poorly made... that is indeed the calculator I used but I wanted to know based on an example:

~6% Beer 1 : OG 1.056, FG 1.010, apparent attenuation 81%

~6% Beer 2 : OG 1.080, FG 1.034, apparent attenuation 56%

What will the major differences be?
 

VikeMan

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Sorry if my question was poorly made... that is indeed the calculator I used but I wanted to know based on an example:

~6% Beer 1 : OG 1.056, FG 1.010, apparent attenuation 81%

~6% Beer 2 : OG 1.080, FG 1.034, apparent attenuation 56%

What will the major differences be?
The beer with the higher FG would have more body, and likely taste maltier and sweeter. And if you were to bottle it, there's a chance you'd make bottle bombs.

Have you taken another gravity reading?

ETA: Or did you already bottle it?

BTW, those two attenuations in your example would be 82% and 58% (not 81 and 56).
 
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KookyBrewsky

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The beer with the higher FG would have more body, and likely taste maltier and sweeter. And if you were to bottle it, there's a good chance you'd make bottle bombs.

Have you taken another gravity reading?
Nope, it’s already been bottled as I simply didn’t know... this was my second stuck brew, the first was another IPA that was a “partial BIAB” kit, some grains were mashed alongside extract... I posted on here about it and nothing could be done as far as I recall, I either had to dump it or bottle it. I repitched that time to no avail.

We’ll see how soon I get bottle bombs. I left them outside this time in slightly cooler / shaded Florida weather. Never had this issue in my near dozen BIAB batches.

RIP
 

doug293cz

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One thing you can do with stuck fermentations is add some alpha amylase to the fermenter. This will eventually reduce any large dextrins or starch to limit dextrins and fermentable sugars. This will take several days to work at fermentation temps. Be careful not to use amyloglucosidase (glucoamylase) or you will also convert the limit dextrins to fermentable sugars, and dry the beer out too much.

Brew on :mug:
 

doug293cz

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you know, an angel just cried in heaven because of that comment....
I thought about adding an aside to the effect of "don't use gluco unless you want to make a brut/low cal brew." The original warning was aimed at those targeting a "normal" FG range with some residual dextrins.

Brew on :mug:
 
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