Lowering final gravity

[BrewMehr]

Recently I've been intrigued by taking a good recipe and increasing the base malt plus adding some corn sugar to raise the ABV to 10-12% - which is usually at least doubling the ABV.

These higher ABV beers turn out great but I'd like to try an get them to finish lighter. They usually finish around 1.028-1.035 for a recipe that should finish around 1.010-1.014 before a increase the fermentables.

So it seems by increasing the base malt I am increasing the complex sugars along with the simple sugars. Either that or my yeast is giving up due to the higher ABV. Should I pitch a second high ABV yeast after the first group is done? Should I lower my mash temp from 152-155 into the mid 140s to get more fermentable sugars? Or is it not realistic to want the higher ABV versions to finish closer to the original recipes?

I had a Surly 8 last week that measured 1.010 finished and claims to be over 10% ABV so this makes me think it is possible.

 

[Qhrumphf]

It's certainly possible to get a big beer that dry. Most of my Belgians I try to get around 1.008. My Quad is just shy of 14%, and finishes at 1.008. "Digestible" as the Belgians say.

Yes, dropping the mash temp will certainly help dry it out. As will increasing the percentage of simple sugar (for my Belgians, I'll go up to 20% of fermentables from sugar). Using a more attenuative yeast will help (not sure what you're using). If you're not using pure O2 to aerate and making a massive starter, you may be getting under-attenuation.

You should also try adding your simple sugars after fermentation starts dying down (if you aren't already). That makes it easier on the yeast initially, and allows your yeast to fully attenuate the maltose before getting to work on dextrose/sucrose/whatever you're using. Equivalent of making sure that the vegetables get eaten before the candy.

 

[BrewMehr]

I'm making a 2 step starter typically -- 2L then 4L so there should be plenty of yeast.

I also use pure O2 before pitching but I don't add any O2 after

I guess it's not a yeast issue since the FG is actually what the recipe calls for.

I like the idea of adding sugars later in fermentation. Is there any contamination concern with this?

 

[Qhrumphf]

When I do fermenter sugar additions, dissolve the sugar in as little water as possible, and then boil it down a little bit. I don't go to a thick syrup or anything, but the goal is to minimize the volume change. Then cool and add directly to the fermenter. Make sure you put a blowoff on when you do it, because fermentation can restart in a big, explosive hurry.