Author Topic: New Brewer - OG & FG Questions.  (Read 875 times)

Offline Benja

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New Brewer - OG & FG Questions.
« on: July 29, 2018, 04:17:54 PM »
Hello all,
I am a new brewer and I have a 5 gallons malt extract kit. I'm about to brew my 6th batch of an IPA recipe that I have that it's coming out very good. The first couple of time I did not care very much about the OG and FG because I didn't want to make things more 'complicated'. Now that I am paying attention to these units, I've found that my OG and FG are way off of what the recipe calls.

My recipe calls for:
OG: 1.058
FG: 1.011


What I am getting is:
OG: 1.045
FG: 1.023


Now, what I think it's weird, is that the last 3 batches I got the same exact OG and FG (1.045,1.023) and I believe I should have a little bit of wiggle room.

I've been using a refractometer to measure the OG and FG (this guy here). This tool can measure Brix and Gravity at the same time so I've been also writing down the Brix numbers that I get and those are:

Brix (OG): 11.5
Brix (FG): 6.2

(and again, the same exact Brix numbers in the last 3 batches)

I should be getting a 6.3% ABV but when I run these numbers into the the Brewers Friends Calculator (link here) I'm getting a 4.26% ABV which is way lower than I wanted to be. See example here

After brew day I will do a primary fermentation for 7 days and then transfer to secondary fermentation for another 14 days, then bottle the beer and wait 14 more days until ready.

My best guess is that I am transferring to secondary fermentation before the fermentation process is completed, and maybe I should leave the beer in one fermenter for 3 weeks and then bottle.

My questions will be:
I am using the wrong tool?
Should I stick to the Hydrometer instead?
Any idea on how I can get closer to my ideal OG and OF?

Thanks everyone for reading my post and your help!
Looking forward to hearing from the community! =)
Happy Brewing!
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Offline tommymorris

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New Brewer - OG & FG Questions.
« Reply #1 on: July 29, 2018, 04:42:11 PM »
Comment deleted. My post was relevant to all grain brewing, not extract.


- formerly alestateyall.
« Last Edit: July 29, 2018, 07:00:35 PM by tommymorris »

Offline mainebrewer

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Re: New Brewer - OG & FG Questions.
« Reply #2 on: July 29, 2018, 05:00:27 PM »
If you are not boiling the full volume of wort; ie, boiling a smaller volume and then topping up with water to the full volume, you are not likely getting a good sample. It is very difficult to fully mix a "heavy" wort with water. With extract, if your volume measurements are accurate, it is more accurate to just use math, ie; # of pounds of extract times the points per pound for the extract divided by the total volume.

You indicate that you are using a refractometer to measure your gravity. Refractometers are not accurate for measuring FG since the sample has alcohol in it. If you are not using a tool to correct your Brix reading when checking FG, look at

SeanTerrill.com

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Offline Richard

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Re: New Brewer - OG & FG Questions.
« Reply #3 on: July 30, 2018, 12:24:14 AM »
Your calculations using Brix are not quite correct, assuming your measurements are accurate. The Brewer's Friend calculator  properly compensates for the presence of alcohol but you must use the calculator properly (see below).

You didn't say how much extract you are using, but the only way your OG can be too low is if your volume measurements are wrong. How much extract are you using, and what kind is it? How much water are you adding? How much are you boling off? What is your final volume? Recipes writers don't know your boiloff, so there can be errors there. If your boiloff is too low you can end up with a larger volume of lower gravity wort.

To use the Brewer's Friend calculator, you need to use a hydrometer and a refractometer. In the top of the page you enter your OG refractometer reading in Brix and adjust the wort correction factor until you get the same result for specific gravity as your hydrometer. For the numbers you gave that is 11.5 and a 1.0272 correction factor to get 1.045 SG. Now, after fermentation you use the bottom part of the page and put in your original Brix, your correction factor, and your final Brix. Putting in 11.5, 1.0272 and 6.2 gives FG of 1.012 and ABV of 4.5% Those numbers are just fine given your low OG.



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Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #4 on: July 30, 2018, 12:42:52 AM »
Hello!
Thanks so much for your response. Before I jump full into this website. Do you think all my problems will solve if I start using the hydrometer instead?

I am not sure what do you mean by 'boiling the full volume of wort'. What I do is put 1.5 gal to steep my grain at 150F for 30 mins, and when that's done I add 8lbs of LME and then add another 1.5 gal and start the boil.

Thanks!

If you are not boiling the full volume of wort; ie, boiling a smaller volume and then topping up with water to the full volume, you are not likely getting a good sample. It is very difficult to fully mix a "heavy" wort with water. With extract, if your volume measurements are accurate, it is more accurate to just use math, ie; # of pounds of extract times the points per pound for the extract divided by the total volume.

You indicate that you are using a refractometer to measure your gravity. Refractometers are not accurate for measuring FG since the sample has alcohol in it. If you are not using a tool to correct your Brix reading when checking FG, look at

SeanTerrill.com
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Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #5 on: July 30, 2018, 12:50:27 AM »
Hello Richard,
Thanks for the information. Regarding your questions:

How much extract are you using, and what kind is it?
8lbs LME Pilsener

How much water are you adding?
I add 1.5 gal, bring it to 150F, steep the grain for 30 mins. Then add the LME and then add 1.5 gal again. So I guess my boil will be close to 4 gal total. I am using this water: https://www.eldoradosprings.com/ I use the spring water.

What is your final volume?
I have never measure that. Final volume will the the volume of the wort when the boil is done?

Thanks again!

Your calculations using Brix are not quite correct, assuming your measurements are accurate. The Brewer's Friend calculator  properly compensates for the presence of alcohol but you must use the calculator properly (see below).

You didn't say how much extract you are using, but the only way your OG can be too low is if your volume measurements are wrong. How much extract are you using, and what kind is it? How much water are you adding? How much are you boling off? What is your final volume? Recipes writers don't know your boiloff, so there can be errors there. If your boiloff is too low you can end up with a larger volume of lower gravity wort.

To use the Brewer's Friend calculator, you need to use a hydrometer and a refractometer. In the top of the page you enter your OG refractometer reading in Brix and adjust the wort correction factor until you get the same result for specific gravity as your hydrometer. For the numbers you gave that is 11.5 and a 1.0272 correction factor to get 1.045 SG. Now, after fermentation you use the bottom part of the page and put in your original Brix, your correction factor, and your final Brix. Putting in 11.5, 1.0272 and 6.2 gives FG of 1.012 and ABV of 4.5% Those numbers are just fine given your low OG.
« Last Edit: July 30, 2018, 01:38:17 AM by Benja »
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Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #6 on: July 30, 2018, 12:54:41 AM »
Some day I am going to be there. =)

Thanks for taking the time to answer though!

Comment deleted. My post was relevant to all grain brewing, not extract.


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Offline mainebrewer

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Re: New Brewer - OG & FG Questions.
« Reply #7 on: July 30, 2018, 09:57:16 AM »
Hello!
Thanks so much for your response. Before I jump full into this website. Do you think all my problems will solve if I start using the hydrometer instead?

I am not sure what do you mean by 'boiling the full volume of wort'. What I do is put 1.5 gal to steep my grain at 150F for 30 mins, and when that's done I add 8lbs of LME and then add another 1.5 gal and start the boil.

Thanks!


You are starting with 3 gallons of wort and boiling for 60 min. So, at the end of the boil you have to add enough water to get to 5 gallons. If you were "boiling the full volume of wort", you would start with 5 gallons plus whatever amount you expect to have evaporate during the boil.


Assuming the beer is at the correct temp, using a hydrometer will eliminate the need for a correction factor to accurately measure FG. OG measurement with a hydrometer will still be subject to the sample not being fully mixed.

If you are not boiling the full volume of wort; ie, boiling a smaller volume and then topping up with water to the full volume, you are not likely getting a good sample. It is very difficult to fully mix a "heavy" wort with water. With extract, if your volume measurements are accurate, it is more accurate to just use math, ie; # of pounds of extract times the points per pound for the extract divided by the total volume.

You indicate that you are using a refractometer to measure your gravity. Refractometers are not accurate for measuring FG since the sample has alcohol in it. If you are not using a tool to correct your Brix reading when checking FG, look at

SeanTerrill.com
BJCP Certified

Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #8 on: July 30, 2018, 02:40:12 PM »
Hello Sir,
Yes, so I start with 3 gallons and then when I transfer to the fermenter I add like 3 more gallons to take the whole volume to 5 gallons total.

What do you mean exactly by 'the beer at the correct temp'? I am assuming the beer needs to be at a certain temperature to use a hydrometer, but what would be that temperature?


Thanks!

Hello!
Thanks so much for your response. Before I jump full into this website. Do you think all my problems will solve if I start using the hydrometer instead?

I am not sure what do you mean by 'boiling the full volume of wort'. What I do is put 1.5 gal to steep my grain at 150F for 30 mins, and when that's done I add 8lbs of LME and then add another 1.5 gal and start the boil.

Thanks!


You are starting with 3 gallons of wort and boiling for 60 min. So, at the end of the boil you have to add enough water to get to 5 gallons. If you were "boiling the full volume of wort", you would start with 5 gallons plus whatever amount you expect to have evaporate during the boil.


Assuming the beer is at the correct temp, using a hydrometer will eliminate the need for a correction factor to accurately measure FG. OG measurement with a hydrometer will still be subject to the sample not being fully mixed.

If you are not boiling the full volume of wort; ie, boiling a smaller volume and then topping up with water to the full volume, you are not likely getting a good sample. It is very difficult to fully mix a "heavy" wort with water. With extract, if your volume measurements are accurate, it is more accurate to just use math, ie; # of pounds of extract times the points per pound for the extract divided by the total volume.

You indicate that you are using a refractometer to measure your gravity. Refractometers are not accurate for measuring FG since the sample has alcohol in it. If you are not using a tool to correct your Brix reading when checking FG, look at

SeanTerrill.com
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Benjamin Armengolli

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Re: New Brewer - OG & FG Questions.
« Reply #9 on: July 30, 2018, 02:51:29 PM »
My guess is that when add that 3 gal. to the fermenter it isn't getting mixed thoroughly.  The wort in your fermenter already is heavier than the water and sinks to the bottom, so when you take a reading you're getting mainkky water from the top.  It's very difficult to geyy it mixed thoroughly enough to get an accurate reading.  The greayy thing bout extract, thigh, is that it's very easy to calculate your ON assuming you know the total volume in your fermenter.   That's the key here.  If you can come up with a way to measure the total volume after you add that extra water, we can show you how to easily calculate your OG.
Life begins at 60.....1.060, that is!

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Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #10 on: July 30, 2018, 03:26:20 PM »
Hello Denny,
What you are telling me makes complete sense. When I'm adding the water I am not stirring the wort because I am afraid that will put some oxygen into it. I guess I have to stir and just be careful.

However, the amount of ABV that I should get, is not directly related if I am stirring or not, right? I guess the amount of fermentable sugars have to be the same.

I think I should sit and have enough of my beer until I start feeling dizzy. Then I can actually tell if they have enough alcohol or not. Lol  8)

Thanks!

My guess is that when add that 3 gal. to the fermenter it isn't getting mixed thoroughly.  The wort in your fermenter already is heavier than the water and sinks to the bottom, so when you take a reading you're getting mainkky water from the top.  It's very difficult to geyy it mixed thoroughly enough to get an accurate reading.  The greayy thing bout extract, thigh, is that it's very easy to calculate your ON assuming you know the total volume in your fermenter.   That's the key here.  If you can come up with a way to measure the total volume after you add that extra water, we can show you how to easily calculate your OG.
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Re: New Brewer - OG & FG Questions.
« Reply #11 on: July 30, 2018, 03:48:33 PM »
Hello Denny,
What you are telling me makes complete sense. When I'm adding the water I am not stirring the wort because I am afraid that will put some oxygen into it. I guess I have to stir and just be careful.

However, the amount of ABV that I should get, is not directly related if I am stirring or not, right? I guess the amount of fermentable sugars have to be the same.

I think I should sit and have enough of my beer until I start feeling dizzy. Then I can actually tell if they have enough alcohol or not. Lol  8)

Thanks!

My guess is that when add that 3 gal. to the fermenter it isn't getting mixed thoroughly.  The wort in your fermenter already is heavier than the water and sinks to the bottom, so when you take a reading you're getting mainkky water from the top.  It's very difficult to geyy it mixed thoroughly enough to get an accurate reading.  The greayy thing bout extract, thigh, is that it's very easy to calculate your ON assuming you know the total volume in your fermenter.   That's the key here.  If you can come up with a way to measure the total volume after you add that extra water, we can show you how to easily calculate your OG.

You are absolutely right, Benja.  Whether or not you stir makes no difference to the gravity.  Fermentation itself will mix things.  The only thing affected is your ability to get an accurate gravity reading.
Life begins at 60.....1.060, that is!

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Offline joelv

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Re: New Brewer - OG & FG Questions.
« Reply #12 on: July 30, 2018, 03:52:08 PM »
After reading the posts so far....

It is very hard to miss gravity with extract. You are likely getting an inaccurate reading. Eight lbs of LME should be around 1.056 in 5 gallons of water. I think Denny’s helped by guessing your sort and water are not mixed.

Your final gravity is off due to using a refractometer without correcting properly and your OG has to be accurate for the correction to work.

You don’t need different equipment to get this right.
— stir your wort and water before measuring OG
— 3 weeks is usually plenty of time for ale yeast to finish when temperature and pitch rate are adequate
— You can use the refractometer for FG as long as you use corrections designed specifically for this. The seanterrill.com site is great

PS - the beer you previously made was likely 5.8%.


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Offline mainebrewer

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Re: New Brewer - OG & FG Questions.
« Reply #13 on: July 30, 2018, 04:36:38 PM »
Hello Sir,
Yes, so I start with 3 gallons and then when I transfer to the fermenter I add like 3 more gallons to take the whole volume to 5 gallons total.

What do you mean exactly by 'the beer at the correct temp'? I am assuming the beer needs to be at a certain temperature to use a hydrometer, but what would be that temperature?


Thanks!

Hello!
Thanks so much for your response. Before I jump full into this website. Do you think all my problems will solve if I start using the hydrometer instead?

I am not sure what do you mean by 'boiling the full volume of wort'. What I do is put 1.5 gal to steep my grain at 150F for 30 mins, and when that's done I add 8lbs of LME and then add another 1.5 gal and start the boil.

Thanks!


You are starting with 3 gallons of wort and boiling for 60 min. So, at the end of the boil you have to add enough water to get to 5 gallons. If you were "boiling the full volume of wort", you would start with 5 gallons plus whatever amount you expect to have evaporate during the boil.


Assuming the beer is at the correct temp, using a hydrometer will eliminate the need for a correction factor to accurately measure FG. OG measurement with a hydrometer will still be subject to the sample not being fully mixed.

If you are not boiling the full volume of wort; ie, boiling a smaller volume and then topping up with water to the full volume, you are not likely getting a good sample. It is very difficult to fully mix a "heavy" wort with water. With extract, if your volume measurements are accurate, it is more accurate to just use math, ie; # of pounds of extract times the points per pound for the extract divided by the total volume.

You indicate that you are using a refractometer to measure your gravity. Refractometers are not accurate for measuring FG since the sample has alcohol in it. If you are not using a tool to correct your Brix reading when checking FG, look at

SeanTerrill.com

Sorry I wasn't clearer on my earlier responses to your questions.
Most hydrometers are calibrated at 60 degrees F, some are 68 degrees F. It will say which yours is somewhere on your hydrometer.
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Offline Benja

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Re: New Brewer - OG & FG Questions.
« Reply #14 on: July 30, 2018, 08:46:36 PM »
Hello Denny,
Thanks so much! That makes sense!

Hello Denny,
What you are telling me makes complete sense. When I'm adding the water I am not stirring the wort because I am afraid that will put some oxygen into it. I guess I have to stir and just be careful.

However, the amount of ABV that I should get, is not directly related if I am stirring or not, right? I guess the amount of fermentable sugars have to be the same.

I think I should sit and have enough of my beer until I start feeling dizzy. Then I can actually tell if they have enough alcohol or not. Lol  8)

Thanks!

My guess is that when add that 3 gal. to the fermenter it isn't getting mixed thoroughly.  The wort in your fermenter already is heavier than the water and sinks to the bottom, so when you take a reading you're getting mainkky water from the top.  It's very difficult to geyy it mixed thoroughly enough to get an accurate reading.  The greayy thing bout extract, thigh, is that it's very easy to calculate your ON assuming you know the total volume in your fermenter.   That's the key here.  If you can come up with a way to measure the total volume after you add that extra water, we can show you how to easily calculate your OG.

You are absolutely right, Benja.  Whether or not you stir makes no difference to the gravity.  Fermentation itself will mix things.  The only thing affected is your ability to get an accurate gravity reading.
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Benjamin Armengolli