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Old 13-03-2013, 11:52 AM   #1
LeithR
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Default Ways to get the FG down to zero

Is there a way to get the FG of an AG brew to below 1000? I ask because I'm diabetic and would like to drive out all residual sugar.

The fact that the final gravity will be higher is of no consequence.
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Old 13-03-2013, 11:57 AM   #2
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Default Re: Ways to get the FG down to zero

I would imagine that would be exceptionally difficult.

The amylases will convert starch to sugars - one of them chops off a maltose molecule (essentially a pair of glucoses), while the other just chops the starch into randomish lengths of glucose chains, what we know as maltodextrin IIRC.

Those don't ferment and are the residual sugar in your beer.

They are digestible and so will alter your blood sugar...

How do you get rid? I guess you would have to mash at a temperature which suppressed the amylase which does the random chopping only letting the end-lopping, maltose-producing one work...?
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Old 13-03-2013, 08:33 PM   #3
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Default Re: Ways to get the FG down to zero

Many thanks Calum,
Couldn't ask for a more concise answer.
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Old 13-03-2013, 08:37 PM   #4
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Default Re: Ways to get the FG down to zero

If you're going to give it a go, let us know how you get on.

Cool project to brew a proper "light-in-the-sugar-sense" beer.

You'll want the highest attenuating yeast you can muster too - have a look through the white labs website, they have some utter animals (well, as animally as yeast get...)!
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Old 13-03-2013, 09:39 PM   #5
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Default Re: Ways to get the FG down to zero

Apparently when making bud light and such (I'm not suggesting this just an example, god forbid ) they use a long multi temp step mash ranging from 60c up to 70c in order to make the mist fermentable wort. Also I believe there's a relationship between mash pH and limit dextrinase activity (some research maybe required) this will also enable further conversion from the beta amylase. Not sure you'll ever get to 1000 but hopefully with the right mash and yeast you should get somewhere near....ish

I believe you can also get enzymes to add to beer to break down the 1-6 chains at the branches of the starch allowing for even more ferment ability.
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Old 13-03-2013, 10:56 PM   #6
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Default Re: Ways to get the FG down to zero

I assume that 1.000 doesn't mean that there are no sugars left, but that alcohols that are lower than 1, and proteins, sugars, etc, that are higher than 1 will average down to 1.000.
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Old 13-03-2013, 11:34 PM   #7
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Default Re: Ways to get the FG down to zero

I think enzymes (Pilsener Enzyme) are also sometimes added to the finished beer to break down residual sugars. Even getting down to 1.000 doesn't mean all the sugar has gone. This is the difference between apparent attenuation (what you calculate from OG & FG readings) and real attenuation (which is how much of the sugar is consumed). If you did ferment out 100% of the sugar, the OG would be less than 1 because alcohol is less dense than water.
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Old 14-03-2013, 08:51 PM   #8
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Default Re: Ways to get the FG down to zero

specialty yeasts or dry enzyme (as already mentioned), if you are a mash brewer then mash really low (more fermentable), a combination or all of these will result in a lower FG, but will also strip the body out of the beer, what makes beer beer is the balance between bitterness and sweetness + the hop flavour, taking any one of those out of the equasion will still make beer, just not as we know it Jim..

such is my understanding anyway
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Old 14-03-2013, 09:09 PM   #9
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Default Re: Ways to get the FG down to zero

This may be a daft thought but what about doing an extract brew with less DME and more sugar.

For example...

500g of Extra light DME
1500g of Brewing sugar

Brewed in a 23L batch the above would see approx 4.2% and finish around 1.000 IME.

Given that around 80% of Extra light DME is fermentable that would only be approx 100g of unfermentable sugars left in a 23L batch.

Adding more extra light DME to taste doesn't really effect the final gravity TOO much, due to it being fairly fermentable and for every point increase due to unfermentable solids, there is an almost equal point decrease due to increased ABV. So be sure not to take the FG as gospel on what's in the pint, the ABV must be taken into consideration.

Low DME, high sugar and hopped out its nut would probably be a good light beer
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Old 14-03-2013, 09:14 PM   #10
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Default Re: Ways to get the FG down to zero

in my experience, beers with too much simple sugars end up not being the greatest, as the OP has said he is an AG brewer his best bet will be to mash low for a more fermentable wort.

At least that way his yeast will stay happy and be able to make a clean beer.

Well.. thats how I see it anyway.
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