Where did the extra sugar come from? Gravity and beersmith headache

[P_Bio]

I brewed my Irish Ale today. This is the 4th time I've made this exact batch and my system is pretty dialed in.

5.5gal batch size

11lb Maris Otter
6oz crystal 40L
6oz crystal 120L
6oz roasted barley

Based on my typically mash efficiency of around 74% (yeah I know it's low) I hit the beersmith predicted pre-boil gravity of 1042 at 8.36gal.

Did the boil and ended up with my exact post boil volume (calibrated using a ruler many times) of 6.76gal.

I put 5.5gal in my fermenter and pitched, the rest is waste and shrinkage. My estimated OG and the usual gravity I hit should be around 1052 but I hit 1058. I know it's not far off but I'm wondering how this could be? My volumes didn't change and my pre-boil OG was spot on. So where could extra gravity come from?

I'm confused. Any help would be great!

 

[gotbags-10]

Hmm. Well a point or two is not out of the norm but 6 is a pretty descent jump. Are you sure you measured correctly? Did you do anything differently? Water, mash temps, grain crush, the way you stirred the sparge. Lots of variables.

 

[Stillraining]

He hit pre. boil spot on so those don't matter at this point. May I inquire as to why you have so much pre boil volume? And are they both in the beer smith cal.correctly? Seems like a lot of volume to loose over all for 5.5 gal. And any Extra boil off from a miss measure will always raise Gravity

 

[P_Bio]

He hit pre. boil spot on so those don't matter at this point. May I inquire as to why you have so much pre boil volume? And are they both in the beer smith cal.correctly? Seems like a lot of volume to loose over all for 5.5 gal. And any Extra boil off from a miss measure will always raise Gravity

I initially thought extra boil off too, but I hit my post boil volume as well. My pre-boil volume accounts for boil off rate, I have a very large diameter kettle so I get 1.6 gal/hr boil off. I then add 1gal for trub loss and chiller.

I do think there is something I am missing with beersmith and my calcs. Regardless I'm sure I'll still have a great beer. I'm just trying to figure out what went wrong because I hit my pre-boil OG fine, so why the difference?

 

[P_Bio]

Hmm. Well a point or two is not out of the norm but 6 is a pretty descent jump. Are you sure you measured correctly? Did you do anything differently? Water, mash temps, grain crush, the way you stirred the sparge. Lots of variables.

The only thing I did differently was modify my water through a small amount of lactic acid (0.2ml-mash, 1ml - sparge) to correct pH. I was wondering if this would cause any difference but because I hit my pre-boil OG I don't think this could be it.

 

[MagicMatt]

...exact post boil volume (calibrated using a ruler many times) of 6.76gal.

I do 5.5 gallon batches, and my pre-boil volume is 6.97 gallons. You're post-boil volume was nearly my pre-boil volume. I know each equipment setup is different, but that seems like a large difference for the same batch size. Not that I'm saying it has anything to do with your issue, but still.

The only thing that caught my attention was the ruler bit. You say you "calibrated" it many times, but exactly how so? Remember that liquid expands when it's heated, so if you were measuring room temp water when you calibrated your volume markings, then you can basically throw out the readings you took of your boiling wort - they're not accurate at all. This could account for a higher gravity, as if the boil level was reading 6.75 gallons, it was probably more like 6 gallons. Hence an extra 3/4 of a gallon boiled off and thus you have more concentrated wort.

Just a thought.

 

[Oginme]

Look at your gravity points. Your pre-boil volume of 8.36 gal * (1.042 -1) * 1000 gives you 351 gravity points.

If you finished with 6.76 gallons your gravity should be: 351 / 6.76 / 1000 + 1 = 1.052

This suggests that one of your measurements was off.

 

[GotPushrods]

11lb Maris Otter
0.6oz crystal 40L
0.6oz crystal 120L
0.6oz roasted barley

0.6 oz of 3 different malts? Do you mean 6 oz? I'm stuck on that...

What did you enter into BS?

 

[P_Bio]

I do 5.5 gallon batches, and my pre-boil volume is 6.97 gallons. You're post-boil volume was nearly my pre-boil volume. I know each equipment setup is different, but that seems like a large difference for the same batch size. Not that I'm saying it has anything to do with your issue, but still.

The only thing that caught my attention was the ruler bit. You say you "calibrated" it many times, but exactly how so? Remember that liquid expands when it's heated, so if you were measuring room temp water when you calibrated your volume markings, then you can basically throw out the readings you took of your boiling wort - they're not accurate at all. This could account for a higher gravity, as if the boil level was reading 6.75 gallons, it was probably more like 6 gallons. Hence an extra 3/4 of a gallon boiled off and thus you have more concentrated wort.

Just a thought.

I calibrated my ruler with water.
Yes you are right that it is difficult to measure post-boil because of expansion. So regardless of that after cooling I can still fill up my 5.5gal to the fermenter and I can measure what is left over, and it is still around 1.2 gallons.

My beersmith settings for my pot are:

Boil volume 8.36gal
Boil off rate 1.6gallons per hour (18" diameter pot)
Cooling shrinkage 4% = 0.27gal
Loss to trub and chiller = 1gal (this could easily come down)

The other reason I'm not sure it's my volumes is my past 15 batches have been perfectly fine. I've hit all of my numbers. Volume makes the easiest sense, and I think this is the culprit but I don't know if it's my settings, I could have just had a brain fart yesterday and just messed up somewhere. But I had plenty of wort left over yesterday, so I don't think I had less than normal which would account for the high OG.

 

[P_Bio]

0.6 oz of 3 different malts? Do you mean 6 oz? I'm stuck on that...

What did you enter into BS?

Yes sorry, 6oz. That was a typo.

 

[P_Bio]

Look at your gravity points. Your pre-boil volume of 8.36 gal * (1.042 -1) * 1000 gives you 351 gravity points.

If you finished with 6.76 gallons your gravity should be: 351 / 6.76 / 1000 + 1 = 1.052

This suggests that one of your measurements was off.

I agree the science doesn't lie. It's just not normal to me so I'm wondering where i made a mistake. Although my system has been pretty dialed in, whenever I miss my numbers it's always that I hit my post-mash gravity but my OG is off. I guess I need to go back to calibrating my volumes.

 

[Twotaureanbrewing]

Look at your gravity points. Your pre-boil volume of 8.36 gal * (1.042 -1) * 1000 gives you 351 gravity points.

If you finished with 6.76 gallons your gravity should be: 351 / 6.76 / 1000 + 1 = 1.052

This suggests that one of your measurements was off.

Im curious about the formula. Subtracting 1 from the expected OG, what does that represent? And what does the 1000 represent?

Trying to learn useful formulas.

Thanks!

 

[MagicMatt]

Im curious about the formula. Subtracting 1 from the expected OG, what does that represent? And what does the 1000 represent?

A gravity point is defined as

which is a fancy way of saying it's the decimal portion of the SG, read as a whole number. Many brewers like to exploit the near linear relationship between (SG -1) and °P to simplify calculations. The Plato degree is thus approximately the points divided by 4.

As an example, a wort of SG 1.050 would be said to have 1000(1.050-1)=50 points. You can then multiply the volume by the points to get total points (essentially sugar content) of the beer. Since when you boil the sugar remains behind, you should have the same number of points in the post-boil wort as in the pre-boil wort. Let's say this example gives us 8 gallons pre-boil, so we multiply 8 by 50 (determined at the beginning of this paragraph) to get 400 points.

Now after the boil, you use this number along with the post-boil volume to determine what the gravity should be. Let's say our post-boil volume is 6 gallons. So divide the volume (6) into the points (400) to get 66.67 pts/gallon.

Since we need this number expressed in terms of SG, we need to get it in terms of thousandths. That's where the dividing by 1000 comes in. Doing so with our example turns 66.67 into 0.06667. Adding 1 yields the expected OG reading of 1.06667. This is more accurate than most hydrometers, so you would generally round to the thousandths place.

 

[Twotaureanbrewing]

Wow! Cool!

Thanks for the explanation and knowledge! Appreciate it

 

[P_Bio]

A gravity point is defined as



Now after the boil, you use this number along with the post-boil volume to determine what the gravity should be. Let's say our post-boil volume is 6 gallons. So divide the volume (6) into the points (400) to get 66.67 pts/gallon.

Which is why I think my issues is my post-boil volume measurement. But doing that points calculation means that if I got 1058 I really had about 6 gallons instead of 6.7. I'm just really surprised by that because I filled my fermenter to 5.5gal and I had way more than a half gallon left over. But I didn't actually measure it. My pot diameter is 18" so a half gallon doesn't even come up to my valve siphon. But I'm convinced thats the problem because there is no other explanation. I'll just have to brew again and make sure I measure everything post boil.

 

[TimH]

So regardless of that after cooling I can still fill up my 5.5gal to the fermenter and I can measure what is left over, and it is still around 1.2 gallons


It blows my mind that you are dumping this amount of wort every batch. Makes zero sense to me.

 

[MagicMatt]

Which is why I think my issues is my post-boil volume measurement. But doing that points calculation means that if I got 1058 I really had about 6 gallons instead of 6.7. I'm just really surprised by that because I filled my fermenter to 5.5gal and I had way more than a half gallon left over. But I didn't actually measure it. My pot diameter is 18" so a half gallon doesn't even come up to my valve siphon. But I'm convinced thats the problem because there is no other explanation. I'll just have to brew again and make sure I measure everything post boil.

My pot is 18" as well, and my dip-tube is about 1/4" off of the bottom. This leaves just over a pint (let's call it 20 oz) behind when I transfer to the carboy.

Also note that the reason the post-boil volume is higher than the final collected volume is not so that you end up with the difference left in your kettle. It's to account for shrinkage from chilling or loss from transferring (as well as deadspace in the kettle, but to a lesser extent). My post boil volume for a 5.5 gallon batch is just over 6 gallons. That doesn't mean I should end up with a 1/2 gallon remaining in the kettle. It's because 6 gallons of boiling wort = 5.5 gallons of room temp wort (roughly speaking, and with a slight margin of error for losses).

It blows my mind that you are dumping this amount of wort every batch. Makes zero sense to me.

I second Tim's concern here. I can't think of any reason to have that much waste. You should be getting as much of what's in the kettle into your fermentor as you can. No need to leave anything behind, especially when you're talking about 20% of your batch. Whats the rationale for this?

 

[Oginme]

It is actually not that uncommon. Look at the recipes in Brewing Classic Styles which are designed for 6.5 gal post boil, 5.5 into the fermentor. Personally, I agree that it is a waste of that much potential beer. OP should be able to cut down at least 1/2 gallon.

Most of my batches are 10 liters into the fermentor with 1 liter of trub and waste left over. This leaves most of the proteins and hops behind in the kettle for most brews. For highly hopped recipes, I go up to 1.25 liters to account for the high loading of vegetative matter.

 

[TimH]

It is actually not that uncommon. Look at the recipes in Brewing Classic Styles which are designed for 6.5 gal post boil, 5.5 into the fermentor. Personally, I agree that it is a waste of that much potential beer. OP should be able to cut down at least 1/2 gallon.

Most of my batches are 10 liters into the fermentor with 1 liter of trub and waste left over. This leaves most of the proteins and hops behind in the kettle for most brews. For highly hopped recipes, I go up to 1.25 liters to account for the high loading of vegetative matter.

No matter what it says in any book throwing out 11 beers is just stupid

 

[P_Bio]

So regardless of that after cooling I can still fill up my 5.5gal to the fermenter and I can measure what is left over, and it is still around 1.2 gallons


It blows my mind that you are dumping this amount of wort every batch. Makes zero sense to me.

I think this was a remnant in beersmith from an earlier system I had where I didn't have a dip tube and wanted to avoid trub into my fermenter when I was first learning.

Stupid or not, it's my money, my beer and this hobby is nice because we all do things differently. What's stupid to you is a big fat "meh" to me. Who cares? Cheers

What I find more comical is why people here get so worked up over how someone else is brewing their beer because "it's just not how I do it". Relax, have a homebrew.

 

[P_Bio]

My pot is 18" as well, and my dip-tube is about 1/4" off of the bottom. This leaves just over a pint (let's call it 20 oz) behind when I transfer to the carboy.

Unfortunately my dip tube doesn't get that close. I think last I checked when I drain into the fermenter and it stops I still have about 0.75gallon left? I'll definitely look into modifying it to get closer, but the way my angle valves are I'm not 1/4" off I'm more like 1/2" off the bottom. But definitely worth rechecking.

I haven't messed with my volumes or system in about a year because my past 10 batches or so have all hit their numbers and been pretty good. I never worried about it. I don't have time. Now that I had this problem it's made me revisit this again and I'll probably reassess my system.

My brewing philosophy is if I hit my numbers and have good beer to drink I'm not too concerned about things. It's only when I run into a problem is when I tinker. Now is a time to tinker.

 

[Stillraining]

My philosophy is much simpler...as long as I'm making good beer cheap... heck with the numbers.


Just spent 200.00 on grain today...that's the only number that really matters to me..

 

[TimH]

I think this was a remnant in beersmith from an earlier system I had where I didn't have a dip tube and wanted to avoid trub into my fermenter when I was first learning.

Stupid or not, it's my money, my beer and this hobby is nice because we all do things differently. What's stupid to you is a big fat "meh" to me. Who cares? Cheers

What I find more comical is why people here get so worked up over how someone else is brewing their beer because "it's just not how I do it". Relax, have a homebrew.

I am relaxed and definitely not worked up you do what you want to do brotha you keep being stunningly inefficient and I will keep getting the most out of my system and not waste a drop in such a wasteful world.