Adding sugar

I had a batch finish at 1.030. It was a partial mash stout and I realize now that I under pitched yeast. I didnt know under pitching was the problem at first so I made a simple syrup and added that after fermentation and it brought my points down. I was talking to the guys at my lhbs and they said I should never add sugar like that, but my question is why? It seems to have worked exactly how it should have.

Curious, what reason did they give for advising you not to.

Well you want to avoid things that have preservatives as it isn't good for yeast health, but since this is post fermentation it doesn't really matter. Folks add table sugar, corn sugar and some syrups to dry out the beer all the time.

Since when does sugar have preservatives in it?

They didn't really give me a good reason, just that it was a bad habit, possibility of infection and a cider taste could be the result.

I've added sugars to multiple beers and haven't had any of those problems so I figured it was BS but I wanted to see if there was in fact a reason for me not to.

Also, I've never seen sugar with preservatives. I'm not saying its not possible but I did check my cupboard to see the sugars I've used in brewing and not one had preservatives listed.

Would someone explain to me how adding sugar syrup brings the gravity down? I'm missing something here. Are we talking about reviving the yeast so that it will resume the fermentation? Because in my experience when the alcohol content reaches a certain percentage it kills the yeast and more sugar is not going to ferment and will just raise the gravity and leave a sweet beer. If I have a stuck fermentation I add some yeast nutrient and stir up the lees. I also take precautions to use a blowoff tube because a full fermenter will foam up big time when the nutrient is added.

Sugar does not cause a cider taste. Many brews use a lot of sugar un the recipes. The possibility ofinfectionis slim in a brew that has fermented that far. Adding sugar after a few days of fermentation is actually a good method. It lets the yeast the more complex sugars firs and they get desert when you add the sugar. I do it all the time with my Belgian brews.

I guess I need to be clear. I had a stout finish at 1.030. After about 8 weeks in primary it still had not gone down. So, I added a simple syrup at this point. There was clearly fermentation. According to my notes it dropped to 1.018.

My understanding was that I would (this is an extremely simple understanding of the chemical process) be adding a chain of simple sugars to a chain of complex sugars, which the yeast can then eat, lowering the gravity.

My lhbs said this was no bueno, but why? Are they just passing along a pervasive myth/misunderstanding?

harrymanback92 said:

I guess I need to be clear. I had a stout finish at 1.030. After about 8 weeks in primary it still had not gone down. So, I added a simple syrup at this point. There was clearly fermentation. According to my notes it dropped to 1.018.

My understanding was that I would (this is an extremely simple understanding of the chemical process) be adding a chain of simple sugars to a chain of complex sugars, which the yeast can then eat, lowering the gravity.

My lhbs said this was no bueno, but why? Are they just passing along a pervasive myth/misunderstanding?

Click to expand...

The gravity of pure ethanol is less than 1. If
You add enough simple sugar you are in essence adding ethanol, so it could be diluting your final gravity. But when yeast kick up they probably chew on the longer chains a bit as long as the desert is still around.