Author Topic: Can't hit my OG #'s  (Read 433 times)

Offline wellertheseller

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Can't hit my OG #'s
« on: September 23, 2018, 01:26:29 PM »
I have brewed up 3 AG batches using Beersmith 3. I brew 2.5 gallon batches and use the scale feature on BS to adjust the recipe. I use a converted water cooler mash tun and regular boil kettle. Brewed a batch today and I came up just a hair short of pre-boil water volume, but not bad (3.31 gallons vs BS estimate of 3.35 gal). BS estimated 1.060 OG and I came up with 1.052. i don't understand why i'm not getting the OG that I should. I pay special attention to mash temp and try to hit 152 deg for 1 hour followed by a 2 step batch sparge. I am using a cheap mr beer hydrometer. should i get another one to double check my #'s? thanks from wellertheseller in TX.
« Last Edit: September 23, 2018, 01:30:58 PM by wellertheseller »

Offline GigaFemto

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Re: Can't hit my OG #'s
« Reply #1 on: September 23, 2018, 03:24:40 PM »
Need more information. You could export your recipe file as a .bsmx and attach it so people could see all the details. Was your post-mash and/or pre-boil gravity correct? If those were also low it could be that your mash pH was off or you over-estimated your mash efficiency in BeerSmith. BeerSmith makes estimates based on the information you put into your profiles, in particular your equipment profile. If your evaporation rate or brewhouse efficiency are wrong there it will result in BeerSmith predictions that don't match your results.  To troubleshoot problems like this you need to make measurements at every step of the process to find out where things went wrong. Once you identify the exact step you can probably adjust either your BeerSmith profile or modify your process.

Here are a couple of videos on setting up equipment profiles:

https://youtu.be/QmW7pwQP5mQ

https://youtu.be/HwEbjOt8OR8

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Offline wellertheseller

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Re: Can't hit my OG #'s
« Reply #2 on: September 23, 2018, 04:07:08 PM »
thanks for the reply....i'm still learning, but should i be taking a hydrometer reading post-mash/pre-boil? I did not do that. I suppose that is how you calculate efficiency.

Offline GigaFemto

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Re: Can't hit my OG #'s
« Reply #3 on: September 23, 2018, 06:40:39 PM »
Yes, BeerSmith has fields to enter post-mash gravity and pre-boil gravity. The first one includes only the mashed grains while the second one contains the contribution from any added extract or sugar. If all you use are grains then they will be the same. This is an important number to record because it tells you how efficiently your mash converted starches to sugars. If you use a hydrometer, but sure to cool the sample down to the calibrated range before you make a measurement: see http://beersmith.com/blog/2018/08/01/adjusting-hydrometer-readings-for-temperature-when-beer-brewing/

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Offline makemorebeer

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Re: Can't hit my OG #'s
« Reply #4 on: November 09, 2018, 08:13:35 AM »
What type of Mash Tun conversion are you using?  My equipment setup is real similar to yours and I've been trying to correct low OG in it for some time with no resolution.  I've got my efficiency set on my profile as low as 63% and that gets me fairly close.  I use a Rectangular converted cooler myself and also batch sparge.  i think the problem, at least in my case comes from Poor grind from the grain seller (northern brewer).  and the inherent efficiency loss from doing batch sparge over fly sparge.

Also, make your life easier and get a refractometer for around $20 on amazon.  Life Changer!

Offline dtapke

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Re: Can't hit my OG #'s
« Reply #5 on: November 09, 2018, 09:20:45 AM »
I'd like to add a question for you, are you compensating temperature on your hydrometer reading?

a reading of 1.052 on a hydrometer calibrated at 68F in a wort solution that is 120F would be 1.060

Also, I'd check the accuracy of your hydrometer, if they get bounced around heavily they can lose their calibration.
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Offline Oginme

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Re: Can't hit my OG #'s
« Reply #6 on: November 09, 2018, 09:58:56 AM »
What type of Mash Tun conversion are you using?  My equipment setup is real similar to yours and I've been trying to correct low OG in it for some time with no resolution.  I've got my efficiency set on my profile as low as 63% and that gets me fairly close.  I use a Rectangular converted cooler myself and also batch sparge.  i think the problem, at least in my case comes from Poor grind from the grain seller (northern brewer).  and the inherent efficiency loss from doing batch sparge over fly sparge.

Also, make your life easier and get a refractometer for around $20 on amazon.  Life Changer!

Poor grind is usually the biggest culprit when it comes to improving efficiency.  I am curious about your comment on the 'inherent efficiency loss'.  If you have a well drained system, fly sparging is more efficient by a few gravity points.  In real life, most people can obtain pretty close to the same efficiency doing a batch sparge versus a fly sparge. 

Also look for process losses which can account for a great deal of efficiency loss (mash tun dead space, loss to trub and chiller, etc.).
Recycle your grains, feed them to a goat!

Offline wellertheseller

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Re: Can't hit my OG #'s
« Reply #7 on: November 14, 2018, 09:57:36 PM »
i am using a home depot 5 gallon water cooler converted to a mash tun. using a bazooka filter. accounted for dead space in BS. I did my 1st readings in the session tab of bs during my last AG brew. got an og of 1.070 vs bs estimate of 1.068 this time around. paid special attention to mash temp. used to think that higher is better, and now i know that lower is better. mashed at 152 for 1 hr. in the design, i lowered my efficiency to 65% in the design. this added more grains to the recipe. during session notes, BS told me that i was around 70% efficiency when i entered pre-boil volume and pre-boil SG....etc. i guess i am happy with that? this was an alpha king clone recipe.

Offline Oginme

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Re: Can't hit my OG #'s
« Reply #8 on: November 15, 2018, 05:46:09 AM »
Let's make sure that we are looking at the same efficiency numbers.  BeerSmith uses two different efficiency numbers: Brew House Efficiency, which is the amount of sugars from the grain bill which end up in the fermenter; and Mash Efficiency, which is the amount of sugars which are collected from the mashing process.  When you enter in the post mash gravity and volume, you are looking at the Mash Efficiency calculations in BeerSmith.  When you fill out the numbers for OG reading and fermenter volume, you are looking at the Brew House Efficiency calculations.

BeerSmith uses the Brew House Efficiency for its calculations.  This is the value that you need to enter into your equipment profile and it will control the amount of sugar from the mash and into the fermenter.

So, in your description of your process, was the Mash Efficiency calculated by BeerSmith at 70% or the Brew House Efficiency?

On another note, the prime range for mash temperatures is from 148F to 158F.  Within this range, the influence on efficiency is pretty minimal.  It is more a matter of effect on the fermentability of the wort produced.

Further, your achievement of 1.070 versus a calculated 1.068 indicates that you have done a good job in your equipment profile, so I would not jump to any changes until several brews demonstrate that you are consistently higher than the estimated target.
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Offline wellertheseller

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Re: Can't hit my OG #'s
« Reply #9 on: November 16, 2018, 06:35:12 AM »
im getting confused. BS estimates for post mash grav 1.055, actual 1.056. my estimated mash eff was 65. actual was 69.7. estimated OG 1.068, actual 1.070, brewhouse efficiency est 65% and it says measured bh efficiency 53.6%. what does this mean? i'm happy with my og #'s, but does all this mean that my low efficiency requires a lot more grain to achieve a certain OG? or am I doing good? this is small batch by the way. 2 gallons total into the fermenter. thanks for your interest in helping this new brewer. I've done about 30 extract batches and about 10 AG batches. still trying to learn all i can.

Offline Oginme

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Re: Can't hit my OG #'s
« Reply #10 on: November 16, 2018, 07:31:39 AM »
When you look at efficiency it should always be Gravity and Volume at each step.  This may be why your overall efficiency is not what your estimate in BeerSmith is set to be.  You may aim for 2 gallon in the fermenter, but how much actually made it into the vessel?  While this may seem onerous at times, taking and recording your gravity and volumes throughout your process will make your efforts more predictable in the long run.

Your batch size should not matter much in terms of your efficiency numbers as I brew 3 liter, 10 liter, and 14 liter BIAB and my efficiency (mash and total) between all three systems is pretty consistent. 

In terms of where your efficiency numbers should be, this is more dictated by your process and volume losses in your system.  The ideal number is the one that you can repeatedly hit every time.  Once you achieve consistency, that is the time to really look at what you can do to improve your efficiency. 

So looking at your numbers, you are getting a little better mash efficiency than estimated by BeerSmith.  Your lower Brew House Efficiency (BHE) combined with the higher than target OG indicates that you had less volume reaching your fermenter than your target.  Where your volume losses occurred should be the first thing you try to track down.  Measuring your actual boil off rate, losses to trub, and other areas where wort is left behind and feeding that information back into your equipment profile will improve your estimations in BeerSmith.

While that is being worked on, entering the efficiency numbers back into the profile will help you 'dial in' the sugar extraction from your mash. 

As you go through this process, feel free to upload your completed recipe as a .bsmx file and ask questions.  There are quite a few people on the forum who are glad to help you make it better.
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Offline BILLY BREW

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Re: Can't hit my OG #'s
« Reply #11 on: Yesterday at 08:09:26 AM »
Grains can have an effect. Are they old? Same with the yeast. Try doing a starter on your yeast to make more cells. Also, you may not be sparging all the sugars out, consider ramping up your grain bill by 10%.
Definitely consider a better hydrometer, they aren't that expensive.
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If it tastes great? Then forget everything everyone says! Have another homebrew and congratulate yourself on a job well done!
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