Sweet wort and high FG

[filbrew]

So I've brewed probably 7 or 8 batches, usually the brewer's best kits, and have had very mixed results. Some brews come out great, but a few of them are coming out very sweet, both before bottling and after carbonation. I'm also having some difficulty hitting my FG's. A few things I've tried:
-experimented with both dry and moist yeasts, and with rehydration
-vigorous aeration of wort (stirred vigorously enough to vortex for 5
minutes prior to pitching)
-increasing the temperature of the fermentation area (in kitchen, usually
between 65 and 70 degrees F)

Would having a low boil volume be a cause of this? I had a 6 gallon brew kettle, but it got damaged and I've been using a 3 gallon kettle for the last couple batches, usually I can only fit about 2 gallons of water in it and still have room for the grain bag and head space for boiling/stirring.

I've also hear that FG's around 1.02 are not uncommon for extract beers. Would switching to all grain resolve the issue? I'm having a hard time justifying the expense until I feel like I really have the hang of what I'm doing.

 

[kh54s10]

What were the sweet beers? Some are supposed to be sweet.

With liquid yeast make a starter.

Aerate even more. Slosh the wort aggressively.

Keep the temperature of the wort (not the room) at the low end of the yeasts range.

You should not be having sweet problems just because it is an extract kit.

 

[kh54s10]

Are you ending up with the right amount?

If it is a kit for 5 gallons and you end up with 4 it would probably be sweet. But it shouldn't be if you topped up to 5.

If you are boiling less than the kit calls for, the hop flavor may be off making it taste sweeter.

I suggest getting the volumes right and see how that goes.

 

[Curtis2010]

Sounds like you are getting a lot of non fermentables in your wort. This would result in high FG and sweeter finish. With all grain this would normally map back to mash temp issues. Are your kits all extract or partial mash?

Boiling is for extracting flavor compounds from hops. Rehydration/dilution (DME vs LME) of your extract or mashing/steeping of grains occurs before the boil so I would not expect that to be an issue. I assume that volume could have an effect on LME/DME utilization, I don't have any info on this, but 2 gallons is very low volume for a 5 galllon (right?) batch. Could in theory be the issue I suspect.

 

[filbrew]

What were the sweet beers? Some are supposed to be sweet.

With liquid yeast make a starter.

Aerate even more. Slosh the wort aggressively.

Keep the temperature of the wort (not the room) at the low end of the yeasts range.

You should not be having sweet problems just because it is an extract kit.

The beers vary, I've had the problem with dunkelweizens, vanilla porters, an apricot ale, and a belgian triple. Didn't have the problem when I made a wit, a weizen, or an IPA. While I realize that some beers are meant to have more malty sweetness, this is above and beyond what I would expect for any style.

 

[filbrew]

Are you ending up with the right amount?

If it is a kit for 5 gallons and you end up with 4 it would probably be sweet. But it shouldn't be if you topped up to 5.

If you are boiling less than the kit calls for, the hop flavor may be off making it taste sweeter.

I suggest getting the volumes right and see how that goes.

The usually top off with purified drinking water before I pitch.

 

[filbrew]

Sounds like you are getting a lot of non fermentables in your wort. This would result in high FG and sweeter finish. With all grain this would normally map back to mash temp issues. Are your kits all extract or partial mash?

Boiling is for extracting flavor compounds from hops. Rehydration/dilution (DME vs LME) of your extract or mashing/steeping of grains occurs before the boil so I would not expect that to be an issue. I assume that volume could have an effect on LME/DME utilization, I don't have any info on this, but 2 gallons is very low volume for a 5 galllon (right?) batch. Could in theory be the issue I suspect.

Partial mash

 

[Curtis2010]

Partial mash

Typically the specialty grains in partial mashes just need to be steeped, not mashed. So I doubt those have much to do w your high FG. My next educated guesses would be low volume or your ferm is not attenuating well, but I would not expect low attenuation to be consistent.

Ferms getting off to a very vigourous start are often seen as a good thing, but can result in the yeasties crapping out early. How was your ferm start?

I suggest trying higher volumes. Ive done a number of 3 to 4 gallon partial mashes with no ill effects for 5 gallon batches, but 2 seems low to me. Maybe someone else can chime in with more knowledge on the effects of low volume on extracts?

For poor attenuation pay close attention to your yeast prep, pitching rate, and wort temps during ferm. More areation before pitching might help. Nutrients should be ok between the extract and steeped grains. I think getting wort temps, and yeast slurry, down to target primary ferm temps is better than pitching at higher temps and causes the yeasties to get off to a less violent start (I do this esp for lagers). You might also try a small (like 1 ltr) test ferm of your high FG wort. If it wont ferm further then I think that indicates high non fermentables...so re pitching wont fix it.

 

[Curtis2010]

What were the sweet beers? Some are supposed to be sweet.

With liquid yeast make a starter.

Aerate even more. Slosh the wort aggressively.

Keep the temperature of the wort (not the room) at the low end of the yeasts range.

You should not be having sweet problems just because it is an extract kit.

Re areation. Try siphoning with a high drop to the surface of the wort (after initially cooling the wort) in addition to aggressive manual areation. An airstone set up makes areation really easy.

Extract concentration levels and boil volumes can have a significant effect on hops utilization. I suggest running the problematic recipes through a brew calculator, at your actual boil volumes, and see how the IBUs calc out. Look at the calc'ed SG too.

Were your SGs on target? Attenuation is measured as a percentage of fermentables...so if you start high you are likely to end high. If too high you can dilute more before pitching.