I can't get anything to ferment below 1.020!

No matter what I do, I simply can't get a beer to finish out below 1.020. Not sure why. I'm always in the temperature range of the yeast I'm using, so why is this? Then again, 6 of my batches never got measured, so a few of those might have finished out lower.

And my latest batch was a Winter Warmer that went from 1.095 to 1.025, which is pretty good, and that was my first time using my new aeration stone. Do you think that the lack of oxygen on some of the other batches might be a reason?

That, and ProMash doesn't realize that MaltoDextrin cannot be fermented, so I think that the beers where I use it, that's some of the issue too.

Just curious. I haven't made any really light beers yet, so it's not like I'm concerned when my stouts don't make it below 20, but still...

Are you brewing all grain recipes or extract recipes?

This could be due to a number of things - too many unfermentable sugars in the mash, a high mash temperature, a low mash temperature, poor yeast health, a low attenuating yeast strain, etc.

Can you tell us a few things about your process, recipes, etc.??

I would be that you are using too much carapils (or other dextrine malt) and a lower attenuating yeast strain. Just a guess.

Could also be your hydrometer. Have you calibrated it to make sure it's accurate?

And could it be that you are doing extremely high Og brews and the yeast just can't go any lower in attentuation?

boo boo said:

And could it be that you are doing extremely high Og brews and the yeast just can't go any lower in attentuation?

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Good point...made me look at Evan!'s signature, and it could be all the other stuff in there besides beer!

Baron von BeeGee said:

Good point...made me look at Evan!'s signature, and it could be all the other stuff in there besides beer!

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True...I am a bit of an adjunct hound. Going to start getting away from that now that I am a bit more experienced...and I have a lager freezer starting tonight.

I mostly brew partial grain, and am careful to do iodine tests to make sure my enzymes have converted.

I do tend to use maltodextrin alot, when it's called for, at least. I like to silken up my mouthfeel. No carapils, though.

My brews do have high OG, but even then, I get low attenuation---and the ABV is not really enough to kill most yeasts on most of my brews.

Do any of you guys think that lack of oxygenation might do it? Or perhaps my lack of making starters?

Sounds like to me that you have done all that is nesessary to ensure your brew goes all the way to completion as much as the yeast will allow.

If I do a 1040 OG brew, I can't expect it to ferment out to 1000. The yeast will only go to about 1008 or so before stopping. It all depends on the amount of unfermentables as was pointed out by sonvolt.

Check the yeast profile to see the apparent attenuation of the yeast you are using.

Evan! said:

Do any of you guys think that lack of oxygenation might do it? Or perhaps my lack of making starters?

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Oxygenation should certainly help if you aren't doing that (at least aeration). As far as a starter goes, I'd hesitate to say it will lower your FG. A starter would probably help in the flavor department, but even if you pitch a smaller amount of yeast it should grow in population to meet the amount of fermentables available...just with more possible off-flavors and a greater opportunity for a bug to grab hold.

Yeah, since I bought a bigger pot, I'd been doing bigger boils, which means that I was topping off with less unboiled water at the end, which, of course, means less oxygen. So I finally bought an aeration kit, and it did seem to help with the first one, the Winter Warmer.

High adjuncts and high OG's mean high finishes. Adjust your OG for non-fermentables and calculate a target gravity based on the expected attenuation. I suspect you'll find out you're hitting the range. What you can do with any software is take out the non-fermentables, note the OG & TG. Put them back in, note the change in the OG. Adding that change to the TG will give you a reasonable idea of what to expect.

I'm not sure what kind of true nonfermentables I've used other than maltodextrin, at least, any that would have any perceivable effect on gravity. I can't imagine that a few ounces of ginger or basil changes the OG too much. Chocolate, a little, perhaps.