Yeast cultivation on stir plate - FG affected?

For the last few batches my buddy and I have been cultivating our yeast on a stir plate for about 18 to 24 hrs prior to pitching. Consequently, our beer has been finishing with a very low FG (there might be other reasons such as high temp, wrong yeast etc) but i wanted to make sure that yeast cultivation is not the sole reason for very low FG/dry beer.

Thanks

drakub said:

For the last few batches my buddy and I have been cultivating our yeast on a stir plate for about 18 to 24 hrs prior to pitching. Consequently, our beer has been finishing with a very low FG (there might be other reasons such as high temp, wrong yeast etc) but i wanted to make sure that yeast cultivation is not the sole reason for very low FG/dry beer.

Thanks

Click to expand...

It's not.

It depends on a multitude of factors not just yeast. Are you overshooting your expected FG? I make a stir plate starter for every beer and have had zero issues. In fact since I started doing this years ago pretty much every beer hits its predicted FG. If you are finishing with a dry beer I would look at mash temps/recipe formulation before yeast pitching rates.

Phunhog said:

It depends on a multitude of factors not just yeast. Are you overshooting your expected FG? I make a stir plate starter for every beer and have had zero issues. In fact since I started doing this years ago pretty much every beer hits its predicted FG. If you are finishing with a dry beer I would look at mash temps/recipe formulation before yeast pitching rates.

Click to expand...

yeah.. there are some possible other issues that i am going to address with my next batch... one of them is the fermentation temp which is at about 72 another one might be the type of yeast that i have been using as well.

In the last few batches my FG was way lower then originally planned.

I guess i am just trying to eliminate all possible causes before my next batch and one them was the yeast started as it seems that since i have been doing the cultivation that is also when all of my batches finished with dry beer but a lot of ALC.

drakub said:

yeah.. there are some possible other issues that i am going to address with my next batch... one of them is the fermentation temp which is at about 72 another one might be the type of yeast that i have been using as well.

In the last few batches my FG was way lower then originally planned.

I guess i am just trying to eliminate all possible causes before my next batch and one them was the yeast started as it seems that since i have been doing the cultivation that is also when all of my batches finished with dry beer but a lot of ALC.

Click to expand...

Fermentation temp shouldn't be it either. What was your yeast and recipe?

What is "way lower than planned"?

Are you brewing all grain or extract? All grain, try mashing at a higher temp. Extract you are always going to have a different finishing gravity because you do not have the ability to choose mash temp.

TyTanium said:

What is "way lower than planned"?

Click to expand...

yeah... way low

planned at 1.020
tested at 1.007

Brandonovich said:

Are you brewing all grain or extract? All grain, try mashing at a higher temp. Extract you are always going to have a different finishing gravity because you do not have the ability to choose mash temp.

Click to expand...

This one was all grain plus 1lbs of dme... i will submit a recipe

1020 is pretty high for most styles. In fact, I'd prefer 1007 to 1020 in most styles.

here is what went into it... (just an FYI.. i posted this few days ago and most people came with the wrong yeast as well as 72 during fermentation)... but if you want to take a jab at it here it is...

12 lbs 2 row briess
2 lbs briess carmel 40l
1 lbs amber dme

60 min .5 simcoe
45 min .5 simcoe
30 min 1 centennial
15 min .5 magnum
15 min yeast nutrient
10 min whirlfloc
1 min .5 citrate

Og 1.078
Sg taken after 11 days 1.008

60 min boil
Mash at 153 with 5gl for 12 he's over night
Sparge with 4 gal
Yeast white labs San Diego wlp090 cultured on a stir plate for 18 hrs
Fermentation at about 72 degrees

So given that recipe, how did you come up with 1.020 for your target FG?

+attenuation factors:
SD Super yeast...super for a reason
Healthy, active yeast
LONG mash, wow
Lower temp
2 row
High temp

-attenuation factors:
2 lbs C40 (wow)
1 lb amber dme

1.007 does seem low for the recipe. Have you checked your hydrometer's calibration in tap water? A few points off obviously makes a huge difference. Also, taste it...does it taste dry like 1.007?

TyTanium said:

1020 is pretty high for most styles. In fact, I'd prefer 1007 to 1020 in most styles.

Click to expand...

i agree but i was going for an IPA with OG that was up there

TyTanium said:

So given that recipe, how did you come up with 1.020 for your target FG?

Click to expand...

i use hopville to do my stuff and that is what came up using 75% efficiency

The overnight mash is going to give you really high efficiency, and you have grains that are completely fermentable, so I am not surprised you are finishing low even though your mash temp was mid-range.

Also, that San Diego yeast is highly attenuative.

Brandonovich said:

Also, that San Diego yeast is highly attenuative.

Click to expand...

That might have been a problem as well... the guy at the store told me that he was out of Cal W001 and this was supposed to be about the same - NOT!!!!

One thing i don't understand is if my efficiency is high therefore my og should be higher therefore my beer should have a higher FG considering the time that was in primary. Am i missing something here?

Higher OG doesn't always mean higher FG. It's more about the percentage of fermentable sugars - dependent on your grainbill, mash profile and yeast.

A big IPA with 1.007 is a goal many strive for...does it not taste good to you? Or are you just asking b/c you were expecting 1020?

Also - wouldn't hurt to check your hydrometer, just to be sure.

drakub said:

That might have been a problem as well... the guy at the store told me that he was out of Cal W001 and this was supposed to be about the same - NOT!!!!

One thing i don't understand is if my efficiency is high therefore my og should be higher therefore my beer should have a higher FG considering the time that was in primary. Am i missing something here?

Click to expand...

Not necessarily. You are extracting fermentable sugars by getting a higher efficiency. If your yeast can handle it (like these yeast can), then they are going to eat up as much as they can. The fermentability of your wort has much more to do with FG than OG does.

TyTanium said:

Higher OG doesn't always mean higher FG. It's more about the percentage of fermentable sugars - dependent on your grainbill, mash profile and yeast.

A big IPA with 1.007 is a goal many strive for...does it not taste good to you? Or are you just asking b/c you were expecting 1020?

Also - wouldn't hurt to check your hydrometer, just to be sure.

Click to expand...

I always thought that yeast will eat as much sugar as it is designed to do so and with higher OG in my mind would mean that there should be a higher FG... i might be completely wrong on this one...

All of the IPA's i have made before had more a body in them (something like dogfish 90 etc). When i took the SG about a week ago i tried it and its just different - dry which is not what i am used to. I have also hopped it with 1 oz of simcoe when it went into secondary so we will see in few weeks once ready to drink after bottling...

drakub said:

....yeast will eat as much sugar as it is designed to do so and with higher OG in my mind would mean that there should be a higher FG...

Click to expand...

That's more true with wine or meadmaking where you're pushing the alcohol tolerance of the yeast...they eat sugar until a) it's gone or b) the alcohol make them stop.

With beer, we typically don't run into that until higher OGs. Usually the limiting factor is available food...that is, they run out of eatable sugars before they are limited by alcohol.

The remaining, residual, unfermented sugars give the beer body and a higher FG.

SO, again, it depends how you're raising the OG, as in, what types of sugars. If you're jacking up the 2-row to a higher OG, it's highly fermentable and you may not have a higher FG. If you're jacking up crystal malts, it's less fermentable so you may have a higher FG. All that to say, there are many variables at play.

drakub said:

here is what went into it... (just an FYI.. i posted this few days ago and most people came with the wrong yeast as well as 72 during fermentation)... but if you want to take a jab at it here it is...

12 lbs 2 row briess
2 lbs briess carmel 40l
1 lbs amber dme

60 min .5 simcoe
45 min .5 simcoe
30 min 1 centennial
15 min .5 magnum
15 min yeast nutrient
10 min whirlfloc
1 min .5 citrate

Og 1.078
Sg taken after 11 days 1.008

60 min boil
Mash at 153 with 5gl for 12 he's over night
Sparge with 4 gal
Yeast white labs San Diego wlp090 cultured on a stir plate for 18 hrs
Fermentation at about 72 degrees

Click to expand...

I think your biggest issue is that you mashed for 12 HOURS!! I don't understand the reasoning behind it when most modified grains are fully converted within 30-60 minutes. A 12 hour mash is going to convert starches that normally wouldn't convert in a "typical" mash. How did you hold the temperature at 153 for 12 hours?

Phunhog said:

I think your biggest issue is that you mashed for 12 HOURS!! I don't understand the reasoning behind it when most modified grains are fully converted within 30-60 minutes. A 12 hour mash is going to convert starches that normally wouldn't convert in a "typical" mash. How did you hold the temperature at 153 for 12 hours?

Click to expand...

There were few reasons for doing the mash overnight (some might not be the correct once as i see it now)...
1. saves time in the morning (especially with two kids)
2. I read that the efficiency will go up and in my mind it was a good thing.

I didn't maintain the temp at 152... what i did is brought the water up to 170 and once the grain is added the temp will drop to about 152-154 or so. Then i would wrap the cooler in massive blankets and leave it over night (last time was between 10pm to 8 am - about 10hrs) and in the morning the temp would be at about 144-146 depending as to where you would take the temp (edge of the cooler vs. middle).

Yeah, that's fine...a lot of guys do the overnight mash w/out issue, especially if it stays above souring range. Certainly you get lots of conversion and highly fermentable wort, so if you're looking for more body and a higher FG, you can always dose in some maltodextrin or something at bottling.

Again, check your hydrometer calibration. Frequently. It's such a critical tool, it needs to be correct.

TyTanium said:

Yeah, that's fine...a lot of guys do the overnight mash w/out issue, especially if it stays above souring range. Certainly you get lots of conversion and highly fermentable wort, so if you're looking for more body and a higher FG, you can always dose in some maltodextrin or something at bottling.

Again, check your hydrometer calibration. Frequently. It's such a critical tool, it needs to be correct.

Click to expand...

I will check that tonight... you mentioned using water... is it supposed to read 1.000... i am assuming

Yes. Water is 1.000 at calibration temp, usually 60 or 68 F. (difference in 8 degrees is small, as long as it's closer to 1.000 than anything else, I'm good with it.