Fermentation issue/High FG

[merlyone]

Hi All,

I've been brewing with my Klarstein (Brewmonk, Hopcat etc.) about 6 months now and I just can't get to desired FG. The OG is usually pretty right but the desired ABV is always few points lower than expected.

Here's my previous lager which got stuck fermentation (abv 3%/5)



And here's my NEIPA receipe (abv usually 4-5%/6)



Here's the equipment profile.



I'm sparging pretty quickly so maybe that could be the problem. Also in NEIPA's the base malt percent is pretty low so could it be that there isn't enough sugars to fermen? Brewfather shows that my mash effiency is usually only 50-60%. I have tried with a starter and without it and feels like it won't matter wich one I go with.

I'm getting pretty frustrated here.

If you have any tips, it would be great! Thanks in advance!

 

[hotbeer]

How well do you control the mash temps? And what kind of mash are you doing, as to me it looks like you have a very thin mash which might not let some of the enzymatic action that can get you more fermentable sugars happen...... though I'm shaky in my understanding of this.

On your batch with the OG of 1.073, the sheet says 18.28 L for mash, where I would probably have been more like 12 liters for the mash and then sparge till I got to my desired fermenter volume, or my desired preboil SG whichever was important that brewday.

Some how I usually find these posts first and I know the least, so maybe this will bump your thread and get some attention.

 

[merlyone]

I have a all-in-one system like Brewmonk so the mash temp should be accurate. I did check one time and if I remember it was ok. It could be that there’s something wrong in my equipment profile and that’s why the mash is so thin. I have to check that one! Thanks!

 

[McMullan]

I'm struggling to imagine any expected deviation from the set mash temperature reduced wort fermentability by that much. I suspect the problem is more to do with yeast stalling. Perhaps you're under pitching? I used Diamond Lager yeast recently and, out of the packet, I thought it was a tosser in terms of fermentation performance, but it attenuated more than predicted, in the end. The starter volume for the ale yeast looks small. Do you aerate/oxygenate the wort before pitching? Do you manage fermentation based on gravity readings? How are you measuring gravity? For ale yeast, you could let the temperature rise above the lower limit after pitching. I'd read the lower value as pitching temperature generally.

 

[merlyone]

I'm struggling to imagine any expected deviation from the set mash temperature reduced wort fermentability by that much. I suspect the problem is more to do with yeast stalling. Perhaps you're under pitching? I used Diamond Lager yeast recently and, out of the packet, I thought it was a tosser in terms of fermentation performance, but it attenuated more than predicted, in the end. The starter volume for the ale yeast looks small. Do you aerate/oxygenate the wort before pitching? Do you manage fermentation based on gravity readings? How are you measuring gravity? For ale yeast, you could let the temperature rise above the lower limit after pitching. I'd read the lower value as pitching temperature generally.

Thanks for answering! I don’t think I’m underpitching because my batches are usually 6% and under 17litres/ 4,5 gallons. One pack of yeast should be enough. I actually didn’t do a starter for the Ale this time. Just pitched it on the surface and shaked it maybe 20sec like I do with every batch. Do you think that’s not enough? But the problem is still with a starter and without it. And with high abv stouts, with ales and lagers. I’m measuring gravity with refractometer and following always the steps in Brewfather. Brewfather shows that tge batch should be good to go and all good. Like I said, usually the OG is pretty close but after that I’m not hitting the FG. I checked the PH too and it was pretty accurate the whole brewing day.

 

[McMullan]

Brewfather recommends packaging under attenuated beer? The problem with predictions made by shiny software, like Brewfather, is they're based on too many assumptions, if they attempt to predict the course of fermentation when standardised procedures aren't being followed. Refractometers are great for sugar solutions, including wort, but not so great once ethanol is present. Are you adjusting your measurements to account for this? A cheap hydrometer is more reliable, imo. I still think you might be under pitching. Unless you're lucky enough to be able to get fresh yeast packs, your pitching rate is just an assumption. Try making a big starter for your next batch. If you are under pitching, fermentation is likely to take longer than the schedule you seem to be following.

 

[merlyone]

Brewfather recommends packaging under attenuated beer? The problem with predictions made by shiny software, like Brewfather, is they're based on too many assumptions, if they attempt to predict the course of fermentation when standardised procedures aren't being followed. Refractometers are great for sugar solutions, including wort, but not so great once ethanol is present. Are you adjusting your measurements to account for this? A cheap hydrometer is more reliable, imo. I still think you might be under pitching. Unless you're lucky enough to be able to get fresh yeast packs, your pitching rate is just an assumption. Try making a big starter for your next batch. If you are under pitching, fermentation is likely to take longer than the schedule you seem to be following.

You could be right. I can taste a little bit of diacetyl in my Ales, so it could be that the yeast is still active ’cause of the under pitching. I usually keg it after d rest (day 10). I’ll try making the starter or pitch 2 packs. Thanks!

 

[merlyone]

You could be right. I can taste a little bit of diacetyl in my Ales, so it could be that the yeast is still active ’cause of the under pitching. I usually keg it after d rest (day 10). I’ll try making the starter or pitch 2 packs. Thanks!

And wait little bit longer of course.

 

[bracconiere]

i'm not sure if it's the case here....but from what i've read 'low attenuation' is usually caused by using a refractometer?

 

[hotbeer]

For your batch with the liquid Imperial Ale Juice did you aerate it well? They have a specific caution about this yeast needing higher levels of dissolved oxygen in the wort.

This strain has demonstrated the need for higher wort dissolved oxygen (DO) levels than most ale strains. Target 20-25 ppm DO or set the oxygen regulator flow to 50% higher than normal.

https://www.imperialyeast.com/organ...nJLzlnxgXpZ8R0uA7X-vBGBq-fYnZgLAaAt5wEALw_wcB

 

[merlyone]

i'm not sure if it's the case here....but from what i've read 'low attenuation' is usually caused by using a refractometer?

Thanks! I’ll switch and double check it with hydrometer next time.

 

[merlyone]

For your batch with the liquid Imperial Ale Juice did you aerate it well? They have a specific caution about this yeast needing higher levels of dissolved oxygen in the wort.

https://www.imperialyeast.com/organ...nJLzlnxgXpZ8R0uA7X-vBGBq-fYnZgLAaAt5wEALw_wcB

No I didn’t! So do you think that shaking the fermentator is not enough? Should I use bottled oxygen? Is it the same thing with london fog? I’ve used that yeast for several batches and have had same issue every time. Shaking about 20-30sec with 1L starter (batch size 15-17L) and without it.

 

[marc1]

Thanks! I’ll switch and double check it with hydrometer next time.

Were you using a calculator to correct for the presence of alcohol in the refractometer reading?

 

[bracconiere]

Thanks! I’ll switch and double check it with hydrometer next time.

check it with both now! there's a calc for that too....

(just be pouring one for the hommies! and still can get a sip after degassing)

edit: but i get a corrected gravity of 0.990 if the refrac is reading 1.017, with an OG of 1.064.....so probably not it...

 

[hotbeer]

No I didn’t! So do you think that shaking the fermentator is not enough? Should I use bottled oxygen? Is it the same thing with london fog? I’ve used that yeast for several batches and have had same issue every time. Shaking about 20-30sec with 1L starter (batch size 15-17L) and without it.

I don't use liquid yeast. For me dry yeast makes everything easy with no fuss. You don't even have to shake the fermenter or otherwise aerate anything.

Imperial doesn't make that statement on several of the other yeasts I looked at. So you'll have to decide and experiment to see if that makes a difference for you. I wouldn't base any for certain assumptions on just one or a few experiences. But that can give you something to consider if you think everything else was performed perfectly.

Maybe some other has experience with that yeast.

As for the London Fog, I don't know. Whitelabs didn't easily provide info about the use of their individual types of yeast, so I quit looking for the info. Maybe you can find out what they say for pitching rates, aeration and best procedures for use.

 

[merlyone]

Were you using a calculator to correct for the presence of alcohol in the refractometer reading?

I have actually. It was just a little off from target.

 

[merlyone]

Thanks all! The issue worked out with a double sized starter! Now I can really start brewing