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Old 03-01-2010, 08:57 PM   #1
Hermit
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I've googled and not come up with a definitive answer. Some people throw out as fact that sugar will invert when boiled in the wort because of the PH. I've seen references where some people say they can taste the difference between plain table sugar and invert sugar in beer while others say they can't. I've wondered about this since both will ferment to 100%. What would be left to taste?

Maybe the answer will pop up at the bottom when I hit the submit button.......

 
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Old 03-02-2010, 03:53 AM   #2
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Quote:
Originally Posted by Hermit View Post
I've seen references where some people say they can taste the difference between plain table sugar and invert sugar in beer while others say they can't.
And I've seen references where people say they can taste the difference between two beer samples, and its later revealed they're from the same bottle.


Perception and prejudice play a huge role in taste, as much as your tastebuds, if not more.

 
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Old 03-02-2010, 07:43 AM   #3
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Two things are required to invert sugar (or break apart the bonds between the fructose and sucrose molecules). Heat and low pH. Boiling wort has both. Whether it has enough of either, I'll leave to someone more expert (although I'm sure those figures wouldn't be hard to hunt up).

As to the difference in taste - both are sweet. If sugar is inverted by extended boiling it may take on a caramel flavour which obviously tastes different. The other thing sucrose supposedly requires the yeast to produce an enzyme to break it down. That enzyme (invertase) has been related to green apple (acetylaldehyde) flavour. How much sugar is required and how true that is I'm not sure. Brewers all over the shop use sugar in their beers although many of the experienced HBers I know who do add it to the boil or in the case of big belgians - incrementally through ferment after high krausen.

 
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Old 03-02-2010, 04:24 PM   #4
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The pH of your wort (~5.2) isn't low enough to get much inversion. Rapid inversion requires a pH around 3. It also works better at higher concentrations than you are likely to use in making beer.
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Old 03-03-2010, 07:35 PM   #5
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Originally Posted by david_42 View Post
The pH of your wort (~5.2) isn't low enough to get much inversion. Rapid inversion requires a pH around 3. It also works better at higher concentrations than you are likely to use in making beer.
OK. You say "rapid". Boiling wort doesn't require rapid. I guess the question becomes will the length of time make up the difference of the higher PH?

 
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Old 03-05-2010, 06:22 PM   #6
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Quote:
Originally Posted by Hermit View Post
I've seen references where some people say they can taste the difference between plain table sugar and invert sugar in beer while others say they can't. .
Doesn't sound credible to me. Sucrose is a glucose and fructose
molecule connected end to end. At low pH you disconnect them
and have an equilibrium mixture of glucose, fructose and sucrose.
What these people are saying is that they can tell the difference
between sucrose and a mixture of the three. Have you ever tasted
corn sugar (glucose) and fructose? They taste exactly the same
as sucrose; for a given amount fructose is the sweeter of the three,
but no actual difference in taste.

Ray
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Old 03-05-2010, 08:03 PM   #7
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What about when the yeast converts these molecules? What are the differences between how yeast reacts with each of these?

 
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Old 03-05-2010, 08:08 PM   #8
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Quote:
Originally Posted by mkory View Post
What about when the yeast converts these molecules? What are the differences between how yeast reacts with each of these?
Cell structures utilize glucose. To break the bonds of sugar chains to reduce them to the basic glucose the cell or another mechanism must produce enzymes or chemicals capable of cleaving the bonds.

 
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Old 03-05-2010, 08:17 PM   #9
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So yeast breaks down sucrose into glucose and fructose, then "eats" both? If so, would it matter what you gave them to eat in the first place? Unless that enzyme that the yeast produces gives the beer a flavor.

 
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Old 03-05-2010, 09:17 PM   #10
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Quote:
Originally Posted by mkory View Post
So yeast breaks down sucrose into glucose and fructose, then "eats" both? If so, would it matter what you gave them to eat in the first place? Unless that enzyme that the yeast produces gives the beer a flavor.
http://www.biochemj.org/bj/026/0531/0260531.pdf

 
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