Electric Brewing Supply 30A BCS Giveaway - Last Weekend to Enter!


Home Brew Forums > Home Brewing Beer > General Beer Discussion > LME and O.G.
Reply
 
LinkBack Thread Tools
Old 02-19-2013, 12:56 AM   #1
jb3218
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
jb3218's Avatar
Recipes 
 
Join Date: Mar 2012
Location: Pittsburgh, Pa
Posts: 57
Default LME and O.G.

I need some info. and I know I'll get the answer here. I made two 5 gallon batches this weekend. One was a milk stout and one was a witbier. I used 6 lbs. of LME for each one. The question I have is why is my O.G. 1.056 for the milk stout using dark malt extract and 1.046 using wheat malt extract. I got the LME from midwest and in the description for the malts it stated that the dark malt had a fermentabilty of 76% and the wheat had a fermentability of 80%. I would think that the dark malt would have a lower O.G. Why is this?

__________________
jb3218 is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 03:40 PM   #2
jdauria
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
jdauria's Avatar
Recipes 
 
Join Date: Sep 2010
Location: Braintree, Massachusetts
Posts: 493
Liked 33 Times on 30 Posts
Likes Given: 24

Default

Did you add lactose to the Milk Stout recipe? That added sugar could be the difference? Using BeerSmith recipe creator, just adding Wheat LME with their general version on file, it lists 1.043. Dark LME 1.041 and if I add add lactose (one pound for the sample) I jump to 1.047.

__________________

Member of the Metro South Homebrew League (Mash-Holes) - Weymouth, MA

Primary - Empty
Secondary - Empty
Kegged - Amber Waves of Grain, Gourd O' Plenty
Bottled - California Common (2nd place, 2014 OSHC).

jdauria is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 04:16 PM   #3
RM-MN
HBT_SUPPORTER.png
Feedback Score: 1 reviews
Recipes 
 
Join Date: Nov 2010
Location: Solway, MN
Posts: 6,875
Liked 790 Times on 658 Posts
Likes Given: 277

Default

Did you top up your fermenter with water? If so, incomplete mixing of the dense wort with the water will give you reading all over the place, from really low to really high depending on where in the mix you got your sample.

__________________
RM-MN is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 06:45 PM   #4
TopherM
Vinz Clortho - the Keymaster of Gozer the Gozerian
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
TopherM's Avatar
Brew Setups
Recipes 
 
Join Date: Mar 2011
Location: St. Petersburg, FL
Posts: 3,873
Liked 425 Times on 336 Posts
Likes Given: 22

Default

LME has a set gravity, because it is already mashed to a set OG. Fermentability indicates how far down from the OG the fermentation will go, i.e., the expected FG. It really has nothing to do with where you start, gravity wise, it just shows where you expect to finish.

All extracts are made from different grains. That wheat LME is made of wheat and pilsner, while the dark malt extract is made of some combination of pale malt/two row and something like black patent (which adds color, but does not add gravity). Each of these grains that make the extract have a different gravity contribution, so their extracted sugars are expected to be different in the extract.

Then, the fermentability numbers aren't linear/dependent on OG...the mash process creates both short-chain sugars that are highly fermentable and long-chain sugars that are not fermentable at all because the yeast can't metabolize them. You can have a higher OG due to a higher % of long-chain sugars and be less fermentable than a lower OG extract containing more short-chain sugars.

Lactose is a long-chain sugar that adds to the density of the wort (gravity), but yeast can not metabolize, so it dillutes/drives down that fermentability variable, but drives up OG and FG.

Anyway, that's the basics. None of those variables are directly dependent on the other, like you are assuming.

The good news is if you move to all grain, you can control all of those variables based on mash temps, whereas you have no control in the extract process beacause you are not mashing, it's already pre-mashed and reduced to syrup.

Let me know if you have any questions!

__________________

Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Mango Habenero Berliner Weisse
Primary #3 - EMPTY!
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Oktoberfest
Keg #2 - Chamomile Honey Wheat
Keg #3 - Pumpkin Ale
Bottled - NONE!

TopherM is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 08:50 PM   #5
jb3218
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
jb3218's Avatar
Recipes 
 
Join Date: Mar 2012
Location: Pittsburgh, Pa
Posts: 57
Default

Quote:
Originally Posted by TopherM View Post
LME has a set gravity, because it is already mashed to a set OG. Fermentability indicates how far down from the OG the fermentation will go, i.e., the expected FG. It really has nothing to do with where you start, gravity wise, it just shows where you expect to finish.

All extracts are made from different grains. That wheat LME is made of wheat and pilsner, while the dark malt extract is made of some combination of pale malt/two row and something like black patent (which adds color, but does not add gravity). Each of these grains that make the extract have a different gravity contribution, so their extracted sugars are expected to be different in the extract.

Then, the fermentability numbers aren't linear/dependent on OG...the mash process creates both short-chain sugars that are highly fermentable and long-chain sugars that are not fermentable at all because the yeast can't metabolize them. You can have a higher OG due to a higher % of long-chain sugars and be less fermentable than a lower OG extract containing more short-chain sugars.

Lactose is a long-chain sugar that adds to the density of the wort (gravity), but yeast can not metabolize, so it dillutes/drives down that fermentability variable, but drives up OG and FG.

Anyway, that's the basics. None of those variables are directly dependent on the other, like you are assuming.

The good news is if you move to all grain, you can control all of those variables based on mash temps, whereas you have no control in the extract process beacause you are not mashing, it's already pre-mashed and reduced to syrup.

Let me know if you have any questions!
I did use lactose and maltodextrin as the recipe called for. As for all grain, I plan on moving in that direction in due time. Another question I have is about the fermenting of the milk stout. I made a starter which went fine. I pitched it on Saturday and when I checked on it on sunday, it was going fine. On Monday it slowed down considerably. I checked on it today (Tues.) and there was no activity. I shook the bucket a little to get it going again but that did not appear to help much. Should I pitch some dry yeast and if so what kind? I have a supply store near me which has a somewhat decent choice of yeast.
I did use lactose and maltrodextrin.
__________________
jb3218 is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 09:11 PM   #6
RM-MN
HBT_SUPPORTER.png
Feedback Score: 1 reviews
Recipes 
 
Join Date: Nov 2010
Location: Solway, MN
Posts: 6,875
Liked 790 Times on 658 Posts
Likes Given: 277

Default

No, you don't need to add more yeast. Your beer is doing just fine, it's just that the yeast have entered the third phase of fermentation. Here's a better explanation than I can give.

http://www.brewgeeks.com/the-life-cycle-of-yeast.html

__________________
RM-MN is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 09:24 PM   #7
TopherM
Vinz Clortho - the Keymaster of Gozer the Gozerian
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
TopherM's Avatar
Brew Setups
Recipes 
 
Join Date: Mar 2011
Location: St. Petersburg, FL
Posts: 3,873
Liked 425 Times on 336 Posts
Likes Given: 22

Default

+1, your timeline looks normal for a good yeast starter. The wort fermented very quickly, but was likely cleaner due to the larger, healthy yeast population. Now, even though the part of fermentation where the yeast eat sugars and convert them to CO2 and alcohol is complete, the yeast will still continue to eat other impurities, esters, and fusels and basically clean up your beer for you if you give them the time to do so. That process only takes another 4-5 days max, but go ahead and let the beer sit in primary for a total of 2-3 weeks from brewday (for most styles). Once the yeast clean up the beer, they'll fall out of suspension and the beer will not only clear but also bulk condition and move more towards it's peak.

__________________

Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Mango Habenero Berliner Weisse
Primary #3 - EMPTY!
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Oktoberfest
Keg #2 - Chamomile Honey Wheat
Keg #3 - Pumpkin Ale
Bottled - NONE!

TopherM is offline
 
Reply With Quote Quick reply to this message
Old 02-19-2013, 10:16 PM   #8
jb3218
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
jb3218's Avatar
Recipes 
 
Join Date: Mar 2012
Location: Pittsburgh, Pa
Posts: 57
Default

Quote:
Originally Posted by RM-MN View Post
No, you don't need to add more yeast. Your beer is doing just fine, it's just that the yeast have entered the third phase of fermentation. Here's a better explanation than I can give.

http://www.brewgeeks.com/the-life-cycle-of-yeast.html
This explanation was very helpful. Now I feel better about my ferm. Thanks!
__________________
jb3218 is offline
 
Reply With Quote Quick reply to this message
Old 02-20-2013, 07:39 AM   #9
jb3218
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
jb3218's Avatar
Recipes 
 
Join Date: Mar 2012
Location: Pittsburgh, Pa
Posts: 57
Default

Quote:
Originally Posted by RM-MN View Post
Did you top up your fermenter with water? If so, incomplete mixing of the dense wort with the water will give you reading all over the place, from really low to really high depending on where in the mix you got your sample.
I did top off with water but I mixed it thoroughly before taking the reading. I'll just wait until fermentation is done and see what I get. It could be worse, I could have got a very low o.g. I'll let you folks know when I know. Thanks!
__________________
jb3218 is offline
 
Reply With Quote Quick reply to this message
Old 02-20-2013, 11:16 AM   #10
RM-MN
HBT_SUPPORTER.png
Feedback Score: 1 reviews
Recipes 
 
Join Date: Nov 2010
Location: Solway, MN
Posts: 6,875
Liked 790 Times on 658 Posts
Likes Given: 277

Default

Here's an experiment for you that won't take long or cost much. Take a clear glass tumbler and fill it 3/4 with water. Pour in some honey and watch what it does. It should go straight to the bottom because it is denser than the water. Now use a short spoon and stir it in. See how well it mixes? Same thing with wort, it just doesn't want to be mixed with the top off water. It's OK, the yeast will find it and chew it up to make beer.

__________________
RM-MN is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools