Sugar Additions

[alwilson]

I'm not really sure how to ask this question, so please bear with my ramblings...

But why does adding sugar (invert or otherwise) cause the beer finish drier, and lower in gravity...

If i have an all malt beer at 1.070, that naturally wants to finish up at 1.016, why does adding enough sugar to up the OG to 1.075 then make it want to get down as far as 1.010?

I can understand the increase in OG, I cannot understand the decrease in FG

Also, whilst on the subject, how much is too much sugar to add, I'm workig on a big wheat beer recipe (46% Pale, 40% wheat and 8% sugar) and the sugar is only there so I can get the FG down a bit further.

Cheers
Alex

[wilsoa11111]

good question, think it might be to do with the yeast being able to utilise the easy sugars so has enough energy to chew through the big starches, bottom line, it does

[ivanmalley]

My understanding is that you use the simple sugar to replace some of the malt derived sugars not in addition to them.

I.e if you add 200g simple sugar you remove 200g complex sugar.

The yeast finds this easier to ferment hence lower FG

[boingy]

I've never really thought about it before but this:

If i have an all malt beer at 1.070, that naturally wants to finish up at 1.016, why does adding enough sugar to up the OG to 1.075 then make it want to get down as far as 1.010?

doesn't sound correct to me, unless you've taken out some malt.

Flavour-wise, 8% sugar will be fine though.

[guypettigrew]

Don't wish to appear difficult, but how do you know it 'wants' to finish at 1.016 without the sugar and 'wants' to finish at 1.010 with the sugar?

Have you done two brews to demonstrate ths, or is there a theory which gives you these numbers?

I've never added sugar to my beers, but have often thought about it, so any info will be much appreciated.

Thanks.

Guy

[Matt12398]

It's because sugar is more fermentable so percentage wise more of the sugars in the wort are fermentable and therefore the residual sugars such as maltotriose are proportionately less than an all malt wort which would have more less easily fermentable sugars.

Think of it this way. If you had 100% malt wort and and 5% of the sugars are unfermentable you'd be left with 5% residual sugars. However if you had 50% malt and 50% sugar then you would have 5% of the 50% malt sugars left and the 50% simple sugars being fermented completely therefore only 2.5% of the total remaining as unfermentable complex sugars from the malt.

[ivanmalley]

Don't wish to appear difficult, but how do you know it 'wants' to finish at 1.016 without the sugar and 'wants' to finish at 1.010 with the sugar?

Have you done two brews to demonstrate ths, or is there a theory which gives you these numbers?

I've never added sugar to my beers, but have often thought about it, so any info will be much appreciated.

Thanks.

Guy

All malts and sugars have a known yield potential.

If you know the typical yield of a malt, usually measured in points per pound per gallon and the average attenuation of the yeast strain then it is a straightforward calculation.

Doesn't always work in practice however.

[Eric]

Because that sugar addition will convert to ethanol with a specific gravity of 0.79 to in turn reduce the final gravity of the whole.

[boingy]

Because that sugar addition will convert to ethanol with a specific gravity of 0.79 to in turn reduce the final gravity of the whole.

Thanks Eric. I'd stupidly assumed sugar fermented down to 1.000. It's double stupid really, as I make wine and I *know* that it gets below that....

[alwilson]

Wow, I love posting these questions before a long weekend and coming back to find all this info! Excellent!

I have done two brews which demonstrate these numbers roughly, and it also kind-of tied up with the numbers some brewing software gave me as well, not spot on to the number - but the same kind of differences.

[Padalac]

You can add more sugar, but its not a good idea to use more than 10% in the initial bill. If you want to add more you should probably add it after the initial fermentation is finished or you may get a high FG.

[alwilson]

aye, cheers Padalac - can I just throw it in boiled up into a syrup (not inverted) and let it ferment or does it need stirring in. Second to that, if I'm going to add say, 8% worth, should I do that in one hit or keep feeding it over a couple of days?

What im trying to achieve is a higher ABV beer (nothing stupid, im talking 8-9% ABV but without that cloying sweetness you get from all-malt beers - as an example harvesitouns old dubh to me is approaching perfection, and I'd like to recreate that, but orkneys dark island reserve is just too alcoholic tasting and cloying.