Incomplete Fermentation past 16days

[JamieGalea]

This fermentation started very slow 48 hours zero activity then started.

OG 1051 day 16 FG is 1025.

Dry yeast US 05
Grain Bill - 7.7lbs pilsner 3.5kg
2.2lbs vienna 1kg


Taste rather sweet I would say the job is not done.
It has a smooth taste and no funky after taste but is sweeter than other brews I ve done.

Mashed on the higher side it was 160f and went down to 152f gradually

Is it due to high number of unfermentable sugars due to vienna and high mash temp ?

Should i add another pack of dry yeast ?

 

[RM-MN]

Is it due to high number of unfermentable sugars due to vienna and high mash temp ?

Mashed on the higher side it was 160f and went down to 152f gradually

Quite likely due to the high mash temperature. My mashes usually complete in less than 30 minutes (a lot less) so in your case you could have denatured most of the beta amylase enzyme before the temperature dropped into its preferred range. If it is unbearably sweet you can use something like Beano to break down more of the starches/dextrines into fermentable sugars. Ask for information about what product and how much of it to use if you decide to go this way.

 

[JamieGalea]

Do you think adding sugar can restart the yeast bringing alcohol up ? Or it might make the beer even sweeter ?

 

[hotbeer]

When it's time to bottle or keg it, then carbonate it higher than you normally would. I think that might hide some of the sweetness. Others might know better about that.

I might wait an extra week to see if it kicks off fermenting again as well as warm it up some to 69°F or better for a few days.

How long do you think your mash temps were on the higher side of 154°F?

 

[JamieGalea]

When it's time to bottle or keg it, then carbonate it higher than you normally would. I think that might hide some of the sweetness. Others might know better about that.

I might wait an extra week to see if it kicks off fermenting again as well as warm it up some to 69°F or better for a few days.

How long do you think your mash temps were on the higher side of 154°F?

I would say it was mashed on the higher side for most of the time 30 - 40 mins

If there is a lot of unfermentable sugars i dont see much to do, i will try to ramp up temperature for 2 days as it has been fermenting at 60f

 

[jerrylotto]

I usually start my mash at low temps (100F) and step up for acid {phytase), beta gluconase, and protein (Proteinase) rests. All three enzymes responsible for this activity are pretty much fully denatured at 130F. Peptidase and Cytase are not far behind. By the time beta amylase kicks in around 135F, you have pretty much excluded all of this other action by denaturing those other enzymes. Heavily modified malts probably don't need it as much, but it doesn't hurt. I always pause for beta rest at around 145F and then spend at least 30 min at 153F which is the sweet spot for beta / alpha balanced activity. Once you get up to 160F, alpha is probably the only thing left.

 

[Kickass]

Three thoughts/questions:

1. how are you measuring gravity? If with a refractometer you need to adjust for the presence of alcohol by applying a math formula. Refractometer’s are very inaccurate for final gravity readings.

2. Vienna malt is still a pretty darn fermentable base malt, and at 25% of your grain bill, that’s unlikely to cause a high final gravity.

3. if your thermometer is accurate and you spent a large bit of your early mash at 160f, you may have denatured some enzymes.

 

[JamieGalea]

Three thoughts/questions:

1. how are you measuring gravity? If with a refractometer you need to adjust for the presence of alcohol by applying a math formula. Refractometer’s are very inaccurate for final gravity readings.

2. Vienna malt is still a pretty darn fermentable base malt, and at 25% of your grain bill, that’s unlikely to cause a high final gravity.

3. if your thermometer is accurate and you spent a large bit of your early mash at 160f, you may have denatured some enzymes.

1 - Gravity is measured by a hydrometer

2- agreed, did this recipe before, had no issues

3- this is most probably the cause and it seems like there is not much one can do but learn from mistake.

 

[Kickass]

it seems like there is not much one can do

Maybe not true. You can add enzymes. That might be a Pandora’s box however. I’ve never used them so can’t give much advice. Others should be able to weigh in with dosage and expectations.

 

[hotbeer]

For the way I mash, I figure 1.25 quarts of water per pound of grain. I use a strike temp calculator to figure out how hot to heat the water to before infusing the grain into it. I've lately been able to get my initial mash temp within a few degrees of the 152 - 154°F that I usually mash at for the entire time I mash. I do sometimes mash out and sparge at 170°F. Depends on the recipe and my mood that brew day.

When you hit your target temp by doing that and you only have one temp to maintain, it becomes pretty easy.

Might later start doing step mashes and having rests, but the ales I am brewing don't seem to need that.

Essentially I'd just wait and see what this batch becomes and then you will learn something. If you mess with it, then you might not get correct perceptions about what the things you did really did since you don't fully know what this beer may have been.

 

[Spivey24]

That seems like very low attenuation for us05. How long was it stuck there? Warm it a little, give it a little shake and wait.

 

[JamieGalea]

That seems like very low attenuation for us05. How long was it stuck there? Warm it a little, give it a little shake and wait.

19 days....

To be honest i just put the temp up a bit and from 1025 it went down to 1023 ... im planning to bottle saturday.

As it is I have an abv of 3.7% , it tastes good and cleared too so it would still be a nice light beer but im hoping it would maybe go down that little bit more by saturday maybe i get a 4% abv atleast

 

[Spivey24]

19 days....

To be honest i just put the temp up a bit and from 1025 it went down to 1023 ... im planning to bottle saturday.

As it is I have an abv of 3.7% , it tastes good and cleared too so it would still be a nice light beer but im hoping it would maybe go down that little bit more by saturday maybe i get a 4% abv atleast

Beware of bottle bombs if it’s still going by then or decides to wake up.

 

[ncbrewer]

Beware of bottle bombs if it’s still going by then or decides to wake up.

Yes - I've had some that finished a little high, but stable. After bottling they started fermenting again. No bottle bombs, but over carbonated. Maybe transferring the beer can prompt it to start back up.