Corn sugar effect og reading?

[surgical_ass]

I don't typically use corn sugar in the boil but the past couple of brews I have. I have noticed that my projected og (just before boil) and my actual og have been off. If I take away the amount of sugar to be used in beer Smith my projected og and my actual og are spot on as they usually are if I'm not using any sugar. When I add the sugar in the boil and take my final reading I don't hit where beer Smith says I should. It's like the hydrometer dosent register the corn sugar in the reading. I do all grain and haven't had any issues with this until I started using sugar. Is there any science behind why the reading would be off? Is there enough moisture in the sugar that it would throw off my reading? What am I over looking? Thanks!

 

[Double_D]

Beersmith calculates my sugar additions no problem. Pre boil gravity is always different then post boil.

 

[surgical_ass]

Beersmith calculates my sugar additions no problem. Pre boil gravity is always different then post boil.

Yes, pre boil is different then post boil gravity. I failed to mention that I calculate boil off in that pre boil gravity reading. I figure this is prob. an absurd question but I thought I would throw it to the people who are much smarter than me in this subject to see if there was any chemistry behind the possibility that corn sugar dosent register in a gravity reading the same way other sugars do.

 

[BlueHouseBrew]

The hydrometer does measure the corn sugar in solution.

Have you taken a hydrometer reading prior to adding the sugar to see if your extracting the amount of sugars from the grain that Beersmith assumes you will? I suspect that this phenomenon may be due to your mash/lauter efficiency being lower than used in the Beersmith calculations. So you may be starting with less sugars than expected (a lower pre-boil / pre-corn sugar gravity) and coincidentally increasing the gravity to about the expected OG with the corn sugar.

The moisture of the corn sugar is relevant if you are measuring it by weight, but this would only have a minor effect and wouldn't explain what you are seeing.

 

[doug293cz]

I have heard that most corn sugar is glucose mono hydrate (https://en.wikipedia.org/wiki/Corn_sugar.) BeerSmith assumes (in it's default ingredient list) that it is pure glucose. So, BS will calculate the SG contribution from corn sugar about 10% too high.

If that accounts for your OG miss, then mystery solved. If not, then there is something else going on.

Brew on

 

[surgical_ass]

I have heard that most corn sugar is glucose mono hydrate (https://en.wikipedia.org/wiki/Corn_sugar.) BeerSmith assumes (in it's default ingredient list) that it is pure glucose. So, BS will calculate the SG contribution from corn sugar about 10% too high.

If that accounts for your OG miss, then mystery solved. If not, then there is something else going on.

Brew on

I would think this is prob closer to what is going on. I have taken the gravity just before I add the corn sugar to make sure I wasn't going to over shoot my est gravity and it was saying I was where I should be then I add the corn sugar and check Final readings and it would be lower than projected. Thanks!