New Giveaway - Wort Monster Conical Fermenter!

Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Unfermentable Sugars




Reply
 
LinkBack Thread Tools Display Modes
Old 12-12-2007, 06:10 AM   #1
jiffybrew
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2007
Posts: 93
Default Unfermentable Sugars

When mashing at higher temperatures you get more unfermentable sugars and thus getting a sweeter beer. What kind of sugars are these? And what makes them unfermentable?
Or... Are all sugars fermentable but it just certain sugars take much longer to ferment?



__________________
jiffybrew is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 08:38 AM   #2
shafferpilot
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
shafferpilot's Avatar
Recipes 
 
Join Date: Sep 2007
Location: Cincinnati OH
Posts: 1,639
Liked 18 Times on 17 Posts
Likes Given: 6

Default

All sugars are fermentable...... depending on what animal is doing the fermentation. Beer yeast is unique for a lot of reasons. One of which is its inability to ferment malto dextrine. I don't know if this is the only unfermentable sugar in beer, but it is the one that I use to back sweeten apfelwine without having to worry about it turning my gallon jugs into grenades. If you look through this chapter on howtobrew.com I think it will provide better answers than I can think of off the top of my head:

http://howtobrew.com/section3/chapter14.html



__________________

A great man knows that he knows NOTHING

shafferpilot is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 09:14 AM   #3
Sir Humpsalot
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Sir Humpsalot's Avatar
Recipes 
 
Join Date: Nov 2006
Posts: 4,043
Liked 81 Times on 65 Posts
Likes Given: 22

Default

It's really all about the length of the sugar molecule.

The illustrative, non-scientific, description I read somewhere is that you can think of alpha amylase (the enzyme active at higher mash temps) as nibbling at the ends of the long chains of large sugar molecules, whereas the beta amylase (active at lower temps) tends to "bite them in the middle".

As a result, alpha amylase leaves longer chains of sugars (more complex sugars) which are more difficult or impossible for mere beer yeast to ferment... though some wine yeasts and other bacterias may still have a field day with them. As a result, an infection, be it a wild yeast or bacteria, can create bottle bombs in otherwise fully-fermented beer.

__________________
In Process: Mango Beer, Homebrewers Pale Ale
Bottled/Kegged:Spicy Light Rye, Rice-adjunct Pale Ale, Mild Bourbon Porter, Roasty Stout, Basic Light Mead, Bourbon County Stout Clone
Up Next: Berlinerweiss, Chocolate Raspberry Ale, and American IPA

Last edited by Sir Humpsalot; 12-12-2007 at 09:51 AM.
Sir Humpsalot is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 09:43 AM   #4
shafferpilot
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
shafferpilot's Avatar
Recipes 
 
Join Date: Sep 2007
Location: Cincinnati OH
Posts: 1,639
Liked 18 Times on 17 Posts
Likes Given: 6

Default

A good way to think of it Humps, but you have your alpha and beta flipped.

http://howtobrew.com/section3/chapter14-1.html


EDIT: Okay it's fixed now

__________________

A great man knows that he knows NOTHING

shafferpilot is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 09:51 AM   #5
Sir Humpsalot
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Sir Humpsalot's Avatar
Recipes 
 
Join Date: Nov 2006
Posts: 4,043
Liked 81 Times on 65 Posts
Likes Given: 22

Default

Quote:
Originally Posted by shafferpilot
A good way to think of it Humps, but you have your alpha and beta flipped.

http://howtobrew.com/section3/chapter14-1.html
I stand corrected!

Fixed.

Personally, I'm not good with fancy names. I just remember lower temps are for watery beers and big barleywines. Everything else, I mash up higher.
__________________
In Process: Mango Beer, Homebrewers Pale Ale
Bottled/Kegged:Spicy Light Rye, Rice-adjunct Pale Ale, Mild Bourbon Porter, Roasty Stout, Basic Light Mead, Bourbon County Stout Clone
Up Next: Berlinerweiss, Chocolate Raspberry Ale, and American IPA
Sir Humpsalot is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 12:40 PM   #6
TexLaw
Here's Lookin' Atcha!
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
TexLaw's Avatar
Recipes 
 
Join Date: Sep 2007
Location: Houston, Texas
Posts: 3,694
Liked 24 Times on 23 Posts

Default

Yep, those unfermentable sugars are dextrines that are larger chain saccharides. The brewer's yeast just can't handle those. Think of it as if you were eating a steak. You can't swallow the thing whole. You have to cut it or bite it into pieces.

It works the same way for yeast, but they don't have cutlery or teeth. If their Mommy doesn't cut up their sugars for them, they can't eat 'em.


TL

__________________
Beer is good for anything from hot dogs to heartache.

Drinking Frog Brewery, est. 1993
TexLaw is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 02:26 PM   #7
david_42
Feedback Score: 0 reviews
 
david_42's Avatar
Recipes 
 
Join Date: Oct 2005
Location: Willamina & Oak Grove, Oregon, USA
Posts: 25,650
Liked 130 Times on 124 Posts

Default

At the other end of the spectrum, gut bacteria have NO problems with longer sugars.

__________________

Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

"I would like to die on Mars, just not on impact." Elon Musk

david_42 is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 04:23 PM   #8
zoebisch01
Feedback Score: 0 reviews
 
zoebisch01's Avatar
Recipes 
 
Join Date: Nov 2006
Location: Central PA
Posts: 5,198
Liked 6 Times on 6 Posts

Default

Quote:
Originally Posted by david_42
At the other end of the spectrum, gut bacteria have NO problems with longer sugars.
Hehe, I learned that the hard way with my first harvest of Jerusalem Artichokes
__________________
Event Horizon ~ A tribute to the miracle of fermentation.

Brew what you like. Do this, and you will find your inner brewer.
zoebisch01 is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 06:01 PM   #9
Dr Malt
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2005
Location: Pacific Northwest
Posts: 287
Liked 11 Times on 11 Posts

Default

Brewers yeast can metabolize sugars made up of one, two and three glucose units ( glucose, maltose, maltotriose). Anything larger than that and they can not metabolize them. Thus, carbohydrate units of of 4, 5 ,6 etc glucose units remain in the beer as unfermentables to provide a sweetness, viscosity and elevated final gravity. Mashing at higher temperatures produces more of these larger carbohydrates due to the high temperature activity of alpha amylase.

This is the chemical version of what what already said. I hope this helps.

Dr Malt

__________________
Dr Malt is offline
 
Reply With Quote Quick reply to this message
Old 12-12-2007, 06:13 PM   #10
charcoal chuck
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2007
Posts: 6
Default

On a similar issue....When formulating recipies and estimating the FG, how does the calculation for apparent attenuation account for unfermentable sugars? Or, is the impacts to gravity from unfermentable sugars small enough to be considered negligable?



__________________
charcoal chuck is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
what to do about very high unfermentable sugar level aaron4osu All Grain & Partial Mash Brewing 7 08-27-2009 02:52 AM
Need an unfermentable way to add citrus to the keg Coastarine Recipes/Ingredients 13 03-11-2009 01:37 AM
Sugars will_cbe Cider Forum 4 06-21-2008 12:36 AM
Intentionally unfermentable? cheezydemon All Grain & Partial Mash Brewing 25 04-07-2008 04:05 PM
I want more sugars! Orfy All Grain & Partial Mash Brewing 6 01-01-2007 07:34 PM