Pre-boil SG Ok. Post Boil Volume Pretty close. Post Boil gravity LOW

[TheLadybugTree]

Help please kind lurkers of the HBT. I have a concerning efficiency problem.

Conversion: 62.7 %
Pre-boil: 67% (9 gal at 1.033 - Brewer's friend expected 1.031)
Ending Kettle: 69% (Had 7.5 gal in kettle at 1.062 - was expecting 1.079)
Brew House: 37% .........37 ?!?!?!?!?!?!!?! What happened?

I brewed my Galaxy IIPA today. Everything was going well. Everything. My PH's were in line. My timing was exactly what I expected. My volumes and temperatures were all pretty close (I will cover one exception) But when it came time to measure the gravity of my wort it was off by 17 points. I am getting a 5.5% beer when I expected a 8%!

I made the recipe using Brewer's friend set to 65% eff. since this is what I have gotten a few times in the past (I am relatively new)

http://www.brewersfriend.com/homebrew/recipe/view/146458/st-patrick-s-galaxy-iipa

Here is a list of all possible reasons I can think of... please forgive me as some them may be very "noob".

1. My mash temp was a bit wonky at first... too high... then I made it too cold... but I was out of room, so I vorlaufed 2 qt and boiled them on my stove and added it back in... temp was about right after that. (grain temp was 148 after mashing was done)

2. I did a 2 hour mash. Never did this before... maybe the cause?

3. When I drew off the chilled wort for the primary, I got 5.1 gallons without tilting keggle. I expected 5.5 So I guess I over boiled a bit. This might be because I actually started the timer when I started boiling the wort as it came out of the mash tun. Next time should I boil those runnings and then start the timer when I am done sparging? Note I did NOT overshoot my target volume as I had 9 gal. which is what I expected. But maybe I took too much water? But then why did I get 5.1g instead of 5.5g? (See how crazy I can be?)

4. After I took the 5.1g, I tipped the keggle and got another 1.5gal. I put this in a separate container as it was somewhat sludgy.

I dunno, I am a little annoyed with this, I was really hoping this beer would be exactly what I planned for. I could take some small differences but this is ridiculous.

Equipment: keggle and igloo with stainless braided.

How could I get the right pre-boil gravity and volume, and then get the pretty close to the post boil volume but way off on the gravity?

Few pre-emptive replies:
yes Double crushed grain
yes checked thermometer against another
yes stirred the mash tun well (though next time I might use drill rod)
yes hydrometer and refractometer agree with one another and are calibrated
yes keggle is calibrated, did it carefully this AM.
yes boil was rolling
no there are no leaks
yes I took two gravity readings of the chilled wort. First as I drew it off and then again once all was mixed together.
yes I would LOVE YOU if you help me trouble shoot this so I can have more success with the next brew.

 

[itchygomey]

I know that with beersmith if I am making a recipe that has sugar added to it, I need to input the recipe without the sugar, write down the expected preboil gravity, and then put the sugar into the recipe. For some reason it ends up all kinds of screwy if I just put everything in and go. I don't know, but maybe the sugar in your recipe is causing a problem.

 

[TheLadybugTree]

Weirdddddddd maybe. Thanks for the tip.


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[acidrain]

You got somewhere around 65% mash efficiency, and then after the boil, left 1.5 gallons and ended up with 31% brewhouse efficiency? At first glance it doesn't seem that far off.
If you add the 1.5 gal to the wort, that would be 6.6 gal., which is way higher than the estimated volume of 5.5 gal., so no, you are not in the ballpark.
Your boil-off was not per recipe AND you left 1.5 gal. behind.

 

[TheLadybugTree]

The 1.5 gal I poured out after was planned into the losses of my equipment profile. I leave 2 gal in the kettle because I haven't got a tube yet. So I had that info right into the brewers friend app. It would be 5.5+ 2 gal in total. But then with too much boil and trub I got 5.1+1.5.

So I was out by .4 gal in my post boil volume.

Or am I missing something?


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[Natdavis777]

When did you draw off your post boil wort to measure the SG? I only ask becuase I had a similar issue once. I took it off the top of the kettle after I cooled the wort and let everything settle. The gravity I was getting by doing this was low, not 17 points low, but lower than expected. By stiring up the wort, it would give me a slightly higher (more accurate) gravity.

I now use a refractometer, and pull my post boil sample right before flameout, while the wort is still boiling.

Just a shot in the dark to see if it helps the issue at hand

 

[acidrain]

Looking back at your original post...

Conversion: 62.7 %
Pre-boil: 67% (9 gal at 1.033 - Brewer's friend expected 1.031)
Ending Kettle: 69% (Had 7.5 gal in kettle at 1.062 - was expecting 1.079)
Brew House: 37% .........37 ?!?!?!?!?!?!!?! What happened?

First, just curiosity, but how did you figure conversion percentage?
9 gal of pre-boil at 1.033 (67% mash efficiency) does not just end up missing sugar. Either your volume measurement was wrong or your SG measurement was wrong.
I suspect as Natdavis777 has said, you got a bad sample because of stratification.
At what point did you add the sugar and DME? After the boil?
You mentioned all the things you did well, but nothing about how you added, dissolved, and mixed in the late additions. Maybe those were stratified?

 

[porterpounder]

If you have hit your pre-boil gravity then your efficiency no longer has any bearing on final SG after the boil.

It is unlikely that you over-boiled if your gravity came out lower than expected. Starting the boil timer when you were not at full boil volume is going to throw off your numbers. How much depends on how long you boiled before you reached final full boil volume. I wouldn't think it would throw you off more than a point or two and again should have made the SG higher, not lower than expected as the wort would have concentrated a bit.

Correct me if I'm wrong on the recipe, but it looks like 3 late additions, (2 # DME, 1# dextrose and .97# ,table sugar). At a 9 gallon PB of 1.031 the late additions calculate out to no more than an available SG of 1.068.

Boiling 9 gallons of 1.031 wort to 7.5 gallons is about a 16% boil-off. In that case without the sugar you would end up with an SG of about 1.043. The sugar additions would add about 1.021 to that (divided extract points per source by volume at time of addition-about 7.5 gallons) So 1 lb. of Dextrose at 46 points adds 1.006 gravity points to the SG, the DME 1.012 and the table sugar 1.0036. That's 1.064. You would need to boil longer at full volume or have a much higher pre-boil from the grain to reach 1.079, more like 1.046 rather than 1.031.

If you boiled down to 5.5 gallons you would have hit 1.079. Your batch size in brewer's friend should be set to 7.5 as that is your final kettle volume.

 

[TheLadybugTree]

When did you draw off your post boil wort to measure the SG? I only ask becuase I had a similar issue once. I took it off the top of the kettle after I cooled the wort and let everything settle. The gravity I was getting by doing this was low, not 17 points low, but lower than expected. By stiring up the wort, it would give me a slightly higher (more accurate) gravity.

I now use a refractometer, and pull my post boil sample right before flameout, while the wort is still boiling.

Just a shot in the dark to see if it helps the issue at hand

When: as it was filling the bucket and then again when it was all in the bucket and has been mixed. Also I use a refractometer too, but never thought of doing it at flameout. Next time!!!

Thanks

 

[TheLadybugTree]

Looking back at your original post...

Conversion: 62.7 %
Pre-boil: 67% (9 gal at 1.033 - Brewer's friend expected 1.031)
Ending Kettle: 69% (Had 7.5 gal in kettle at 1.062 - was expecting 1.079)
Brew House: 37% .........37 ?!?!?!?!?!?!!?! What happened?

First, just curiosity, but how did you figure conversion percentage?
9 gal of pre-boil at 1.033 (67% mash efficiency) does not just end up missing sugar. Either your volume measurement was wrong or your SG measurement was wrong.
I suspect as Natdavis777 has said, you got a bad sample because of stratification.
At what point did you add the sugar and DME? After the boil?
You mentioned all the things you did well, but nothing about how you added, dissolved, and mixed in the late additions. Maybe those were stratified?

Conversion: Brewer's friend just lists it as one of the efficiency. I'd be lying if I said I knew where it comes from.

Addition: I added DME, Sugar, Dextrose around the 15 min. mark while it was a rolling boil. What do you mean by stratified? Layering of densities? I don't think that will be the cause if it boiled 15 minutes

Thanks for ideas.

 

[TheLadybugTree]

If you boiled down to 5.5 gallons you would have hit 1.079. Your batch size in brewer's friend should be set to 7.5 as that is your final kettle volume.

Your math is stupendous. I had a trouble keeping up but I think I agree. However, in brewer's friend you have the option to choose whether you set it to kettle or fermenter volume. My fermenter was hoping to be 5.5. Kettle 7.5

I think you have hit something here. If I set my recipes up in the future as Kettle volume the program will handle it better.

I think I figured out why Pre-boil gravity could be right but not post: The calculator I used online must have an error where if you say you will add 2# dme, 1# sugar, etc. and it is a 5.5 gallon batch then it assumes all that sugar stays in the 5.5 gal. It doesn’t take into account the losses of sugar in the kettle. Normally efficiency might be a bit low because you lose some sugar in the grub, but in my case I am losing LOTS in my dead space because I have no take off arm. So even though it is calibrated to my equipment and losing 2 gal in kettle, it knows the water will be missing but not the sugar. I guess in the future I will just have to do gravity tests in the end of the boil while i add sugar until i hit my OG. I am pretttttty sure this is the reason. Possible fix: add sugar to fermenter, though this might be a LOT of sugar to pick up 17 points.

Maybe this is a cop out to blame the program... But if I get a tube for the inside at least the program will get way closer by guessing and I can fine tune during the boil. Also, it is worth trying your idea and doing kettle efficiency instead.

 

[TheLadybugTree]

I know that with beersmith if I am making a recipe that has sugar added to it, I need to input the recipe without the sugar, write down the expected preboil gravity, and then put the sugar into the recipe. For some reason it ends up all kinds of screwy if I just put everything in and go. I don't know, but maybe the sugar in your recipe is causing a problem.

What is your kettle like? How much dead space?

 

[TheLadybugTree]

My math says if I boil 1 kg (2.2 lb) DME and 1.5# sugar and add to fermentor I should be back at the OG i was expecting. Maybe this would be smart since it will restore some balance to the flavour. I am fearing a super hoppy APA. Not that there is anything wrong with that....

Actually I bet it'll be a 6% beer with 85 ibu. Probably a final gravity of 1.014. This my prediction. Would be tasty.

Taking all bets. I'll deliver the results in two weeks. Or maybe 2 days what with how fast the Nottingham is chewing away.

Is there any forum policy against gambling. Haha.

Edit: Oops, that real would throw it off, that is what I SHOULD have done. 1 # sugar and 1 pound of DME will give me 17 points in 5.1 gal I think!

 

[porterpounder]

Give the extra additions a shot. Just make sure you have enough space in the fermentor to accommodate the extra volume. Nothing like a beer volcano!

 

[TheLadybugTree]

Using a old school bucket this time luckily both my carboys were full. That felt good to say. Lol


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[TheLadybugTree]

Update: not going to do the additions. Talked to the guy at LHBS (Neil) and he gave some solid advice. I have a balanced APA or IPA right now. If I add sugar I will have something with enough alcohol but not enough IBU.

Lesson: Do not count on brewer's friend for late kettle additions when using 'fermentor' as the target.

 

[Natdavis777]

I use a keggle too, I figure you are in the process of upgrading to a pick up tube, but if not, I highly recommend it. I just have a compression fitting inside with a side pick up tube. Leaves about 1.5L. Keeps out of the middle of the kettle though so I can still get a good whirlpool

 

[TheLadybugTree]

I am indeed. Just waiting for money and whatever.

I also want to start whit pooling eventually. But pumps seem expensive. I mostly just love the idea of keeping everything sealed while the chiller is in and it stirring for me. Also during the hop stand. Woooo. I'm excited. Any recommendations for a pump?


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[Natdavis777]

My wife picked me up a SS chugger for my birthday. I couldn't be happier with the ease and advantage it's given me. Got all my quick disconnects on amazon for good deals, and some silicone tubing at the LHBS. You can still do successful hop stands without a pump though. A decent stir after flameout with your paddle or spoon and soaking your hops for you desired hop stand time will still net good results.


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