US05 ends at 1.020

[derbedeu]

Hello,

I run a small brewery (55 gal/batch) and mainly use the same recipe, with very few modifications. I generally start with an OG of 1.055-1.060, and always use US05. Which I harvested and washed, very cautiously, with excellent results. I basically have a big stash of US05 cells. However, the last 2 brews I made, although I always make a starter, ended up quite far from the planned FG. Namely, 1.020-1.022.

I run a very thorough process, so strike/mash temp is always within limits (68 Celsius/155 Fahrenheit), I always check the saccharification with iodine, and it always is positive. However, although the vast majority of my batches (regardless of the recipe I brew) end up at 1.008-1.012, the last 2 seem to have stopped earlier. Needless to say, fermentation temp is also steady, 20 Celsius (68F)

The only thing that I changed, although I really doubt that this has a real impact, the last 2 starters I made were with LME, instead of DME. Again, I emphasize, my brewery is very clean and the possibility of the yeast to degrade is almost null.

Please excuse me if that was already posted, anyway, thank you for your input.

Cheers!

 

[WBB]

I’m not sure you’re looking for. If the FGs for all your previous batches end up in the 08-12 range and then the last two end up in the 20-22 range and the only difference, so you say, is that you used LME instead of DME. Well I think you have your answer, although I didn’t really see a question.

 

[Gnomebrewer]

The first check in all of these high FG threads: have you been using a refractometer, or hydrometer, for your FG measurement?

 

[derbedeu]

The first check in all of these high FG threads: have you been using a refractometer, or hydrometer, for your FG measurement?

Hey, I always use a hydrometer for my FG reading. For OG, I use both a refractometer and a hydrometer. Also, checked 4 days ago, let it rest for another 2, ckecked again, no change. I even raised the temperature a few degrees. However, just because of LME in the starter, such things can happen? I sort of doubt.

 

[Gnomebrewer]

However, just because of LME in the starter, such things can happen? I sort of doubt.

Yeah, I agree. Unless the particular batch of LME was bad (eg. sulfites), but I'd say it's unlikely.
How many generations is your yeast up to?
Have you recently calibrated your thermometer (a low temperature reading, meaning a higher actual mash temperature, would explain a high FG)?
Does the beer taste sweet and cloying? An 1.020 FG from dextrins doesn't taste anywhere near as sweet as a 1.020 FG from poor attenuation.

 

[beernutz]

Hard to say but I would guess the culprit might found among inappropriate pH, lack of aeration, and/or poor yeast health.

 

[kingmatt]

What generation are you on for your yeast? Eventually they will start crapping out on you so it may be time for a fresh pitch.

 

[derbedeu]

Yeah, I agree. Unless the particular batch of LME was bad (eg. sulfites), but I'd say it's unlikely.
How many generations is your yeast up to?
Have you recently calibrated your thermometer (a low temperature reading, meaning a higher actual mash temperature, would explain a high FG)?
Does the beer taste sweet and cloying? An 1.020 FG from dextrins doesn't taste anywhere near as sweet as a 1.020 FG from poor attenuation.

Basically, the yeast is generation 1. I mean, I harvested it, washed it and then made a starter. Anyway, it's fresh, and the starter I made smelled and tasted perfect.
I have not calibrated this particular thermometer, but I checked it with another one - the line bringing in the strike water has one, the readings are similar.
The beer tastes a bit sweet, it is not an overwhelming sweetness, it is just mild. With a bit of dry hopping even that would be hard to notice.

Thanks a lot for your reply.

 

[derbedeu]

What generation are you on for your yeast? Eventually they will start crapping out on you so it may be time for a fresh pitch.

Basically, first generation after harvest (I do not include the starter here).

 

[derbedeu]

Hard to say but I would guess the culprit might found among inappropriate pH, lack of aeration, and/or poor yeast health.

Hey, thanks for your points. I use municipal water, whose quality is pretty good and also steady (previous batches didn't suffer), which I know it can degrade, so I have to check the pH and not take it for granted.
I am using a large strainer to separate the hops from the beer, before cooling it, and I assume the pouring/straining process aerates the beer quite a lot. Again, previous batches (many) did not show this problem.
The yeast seemed (educated guess, no lab equipment here) active and healthy, but I guess that might be a bit far from reality, so I will look more accurately into it.

Thanks a lot for the reply.

 

[Gnomebrewer]

Basically, the yeast is generation 1. I mean, I harvested it, washed it and then made a starter.
Thanks a lot for your reply.

How many batches of beer before this one was it since you pitched a new packet of dry yeast? That's how many generations old it is.

 

[derbedeu]

How many batches of beer before this one was it since you pitched a new packet of dry yeast? That's how many generations old it is.

Well, I harvested quite a large amount (2 gallons), washed it, and keep using it since - maybe 5 months old. So basically I keep making starters from the one I harvested. Thing is, 2 weeks ago I made a batch, fermented to 1.010. 2 weeks after, from the same strain, same generation, just a different starter, ends at 1.020. Weird.

 

[Gnomebrewer]

How much sugar (dextrose, sucrose, glucose etc) do you use in your beer?

 

[derbedeu]

How much sugar (dextrose, sucrose, glucose etc) do you use in your beer?

I don't add anything aside of malt. Usually, I go for 70% pilsner/pale ale plus 30% vienna/munich/amber.

 

[bucketnative]

Have you checked the accuracy of your temperature measurement devices/controllers used during the mash?

 

[dmtaylor]

This is a tough one. My guess is it's related to the yeast in some fashion. Might be a bad batch of yeast, maybe it wasn't stored right, was half-dead, got contaminated, and you've got some other unintended yeast doing the work for you. That's my best guess. Sounds like you're doing everything right otherwise so I kind of want to blame manufacturer, shipment, or storage of the yeast before it got into your hands. Try a brand new yeast batch, and problems might just disappear.

Cheers and good luck.

 

[derbedeu]

This is a tough one. My guess is it's related to the yeast in some fashion. Might be a bad batch of yeast, maybe it wasn't stored right, was half-dead, got contaminated, and you've got some other unintended yeast doing the work for you. That's my best guess. Sounds like you're doing everything right otherwise so I kind of want to blame manufacturer, shipment, or storage of the yeast before it got into your hands. Try a brand new yeast batch, and problems might just disappear.

Cheers and good luck.

Well, this is my fear too. This is actually the reason I posted here, to make sure I am not the only one blaming the yeast. The yeast is, however, stored very well, at least that's what I think (glass jars at 1C/34F).

On the other hand, I wonder if maybe the LME profile that I used for the starter could have affected the fresh yeast viability. It was a blonde tripel, and I never bothered to see what the starter's FG was before separating it and pitching it into my wort :/.

 

[dmtaylor]

I doubt the starter's FG had anything to do with anything.

You cannot control the yeast before your receive it. It could have been mishandled anywhere along the way before you got it.