The CRAZY cold weather...

[iamwhatiseem]

So in the little brewhouse I have, we are adding heating this summer. All last summer I fermented in a small area with a window A/C that has done well.
Last Saturday I brewed a brown ale and used the fridge as the chamber with a Johnson Controller.
I didn't pay attention to the weather, and the temp outside dipped into the freaking 30s IN MAY!! Long story short the ambient temp fell to 48 degrees and fermentation stopped.
It has been sitting in there ever since. My chest freezer in the house that I use during the winter to ferment is full of frozen meat we stored up during the pandemic.
QUESTION - I can probably stuff the meat into the two fridge freezers and ferment in the chest freezer as normal, other than allowing the wort to warm up... do you believe the yeast will fire back up on it's own - or should I re-pitch?

Thanks for the responses!

 

[VikeMan]

other than allowing the wort to warm up... do you believe the yeast will fire back up on it's own

Most likely.

 

[RM-MN]

So in the little brewhouse I have, we are adding heating this summer. All last summer I fermented in a small area with a window A/C that has done well.
Last Saturday I brewed a brown ale and used the fridge as the chamber with a Johnson Controller.
I didn't pay attention to the weather, and the temp outside dipped into the freaking 30s IN MAY!! Long story short the ambient temp fell to 48 degrees and fermentation stopped.
It has been sitting in there ever since. My chest freezer in the house that I use during the winter to ferment is full of frozen meat we stored up during the pandemic.
QUESTION - I can probably stuff the meat into the two fridge freezers and ferment in the chest freezer as normal, other than allowing the wort to warm up... do you believe the yeast will fire back up on it's own - or should I re-pitch?

Thanks for the responses!

Are you sure the two didn't happen in reverse, the yeast stopped and the temperature fell? Often the fast part of the fermentation where CO2 is produced only lasts 2 to 3 days.

 

[iamwhatiseem]

Are you sure the two didn't happen in reverse, the yeast stopped and the temperature fell? Often the fast part of the fermentation where CO2 is produced only lasts 2 to 3 days.

Positive.
I pitched Sunday afternoon from a yeast starter.
I checked it Monday afternoon and it had just started the fast ferm...only maybe 3/4" kruasen. The temps fell Monday night, I checked early afternoon Tuesday and the fermentation definitely stopped cold. The bubbler was even, the krausen had mostly fell. That would have been the fastest fermentation in history. And for Windsor yeast it was way-way less vigorous than usual. I have brewed 100's of beers, so I am positive it dropped out early due to temp fall.
Thanks for response

 

[iamwhatiseem]

I managed to empty the chest freezer, I have sat the fermenter on the floor (not in the freezer obviously) and will let it sit at room temp while the freezer warms back up. I will watch to see what happens and probably repitch Monday if it hasn't fired back up on it's own.

 

[Transamguy77]

I was Going to say I would just bring in the fermenter and let it warm up in your house and see if it starts back up but it sounds like your already doing that.

 

[iamwhatiseem]

Well darn, all the beers I have made this has never happened. Sure I have had a few stalled fermentations that slowed down, then even as late as 2 days later fire back up. But never fully drop out, Krausen and all. Before I went to bed as best I could I stirred the fermenter a bit... got up this morning...nothing. The room is 72 degrees.

 

[VikeMan]

Before I went to bed as best I could I stirred the fermenter a bit... got up this morning...nothing. The room is 72 degrees.

I'm hoping you mean that you gently swirled (at most) the fermenter. You shouldn't be opening the fermenter and stirring the beer at this point, as that would aerate it and cause oxidation.

got up this morning...nothing. The room is 72 degrees.

What's the temperature of the beer itself? When you put your cold beer in a 72F room, it takes a while for the beer to warm up. Your fermenter full of beer is a pretty effective thermal mass.

I would give it some more time. Also, do you have a hydrometer?

 

[iamwhatiseem]

Yeah... definitely not actually stirring, just kind of swirling the fermenter. The strip gauge says it is 68 - 70 I would say.
I dropped my hydrometer a couple years ago and never bought a new one. I do have a refractometer...but not going to do a lot of good with that. It isn't going to hurt it to sit for another day of course, so after work tomorrow if still nothing I will just pitch again.
Just really strange, there is no way it fermented properly in a little over 24 hours.

 

[VikeMan]

I do have a refractometer...but not going to do a lot of good with that.

If you know what your OG should have been, and are confident you were probably close to it, you can use a refractometer calculator to "back into" a pre-fermentation refractometer number estimate, take a real refractometer sample now, and assess where you are.

ETA: I'm not claiming that attenuation was finished...just wanted to dispel the notion that the refractometer can't be used at this point.

 

[Brooothru]

If you know what your OG should have been, and are confident you were probably close to it, you can use a refractometer calculator to "back into" a pre-fermentation refractometer number estimate, take a real refractometer sample now, and assess where you are.

ETA: I'm not claiming that attenuation was finished...just wanted to dispel the notion that the refractometer can't be used at this point.

^^^^ Agree.

I've actually had very good results using a refractometer both during fermentation as well as after completion. As long as you have the original gravity and use an online calculator, you can get a good idea of current and final gravity, thus ABV. The Brewer's Friend calculator is the most accurate in my estimation, but they all have the same underlying math. A few years back I tracked at least 12-15 fermentations of both beer (various styles) as well as wine. Every 'fermenting' reading was within 2~3 points SG of a calibrated hydrometer, and terminal gravities were never off by more than one point, often identical. Close enough for my needs.

Brooo Brother

 

[iamwhatiseem]

Hmm... learn something everyday.
I didn't think a refractometer was useful once alcohol is present?
I did not take an OG, but with my efficiency average it should have been close to 1052...I'll try that

 

[VikeMan]

I didn't think a refractometer was useful once alcohol is present?

Alcohol skews the reading, because it has a different refractive index than water. But also, the kinds of sugars/dextrins in wort/beer are mostly not sucrose, which is what refractometers are calibrated for. These are the reasons why a calculator is needed, for both the OG, and for the FG (along with OG).

 

[iamwhatiseem]

So I remember I did change the grain bill a bit, so I entered everything into Beersmith with accurate water amounts and gallons of wort afterwards.
My OG was probably very close to 1049.
The refractometer Brix is just above 9.... let's say 9.2.
That would make my est. ABV at 2.69%...waaay below the expected avg. of 5.2. Almost half, so indeed as suspected the fermentation halted.
I am going to take my own advice I have given beginner brewers here all the time - just relax. Be patient.
I am going to give it another 24 hours, well by the time I get off work tomorrow be more like 30 hours...anyway... if it hasn't fired back up I will repitch.
If it hasn't... it is a mystery as to why the healthy yeast from a starter didn't reanimate.

 

[VikeMan]

My OG was probably very close to 1049.
The refractometer Brix is just above 9.... let's say 9.2.
That would make my est. ABV at 2.69%...waaay below the expected avg. of 5.2. Almost half, so indeed as suspected the fermentation halted.

Given your numbers, I'd put the ABV at more like 3.5%, not that it matters much. Attenuation obviously wasn't finished, unless this was a very unfermentable wort.

 

[Brooothru]

Hmm... learn something everyday.
I didn't think a refractometer was useful once alcohol is present?
I did not take an OG, but with my efficiency average it should have been close to 1052...I'll try that

It's true that alcohol skews the results. However, the underlying math that the calculators use in subsequent steps take this variance into account and 'skew the numbers back' to give a fairly accurate representation of actual specific gravity. There is a name for the equation that I can't remember, likely named for the mathematician who created it. It basically removes, or at least corrects for, the error introduced by the alcohol refractive variable.

The other error that @VikeMan pointed out is the refractive error caused by different "toses" (sugars). "Sugar" (glucose) has a refractive index of "1" on a brix refractometer. Maltose has a wort refractive index of approximately 1.04. When I measure wine brix there is no refractive index correction. When I measure beer brix I use 1.04 as a corrective variable.

By using the formulae and the calculators you can get some pretty accurate numbers, certainly within the probability of error, that temperature and visual acuity introduce when using a hydrometer.

Brooo Brother

 

[iamwhatiseem]

Given your numbers, I'd put the ABV at more like 3.5%, not that it matters much. Attenuation obviously wasn't finished, unless this was a very unfermentable wort.

You know I forgot to change the variable, left it at 1 - so you are right. Nevertheless, same conclusion... it wasn't done.

Cheers

 

[VikeMan]

"Sugar" (glucose) has a refractive index of "1" on a brix refractometer. Maltose has a wort refractive index of approximately 1.04.

I think perhaps you're confusing "refractive index" with "correction factor." Only empty space has a refractive index of 1.

 

[Brooothru]

I think perhaps you're confusing "refractive index" with "correction factor." Only empty space has a refractive index of 1.

You are indeed correct. Here's the math for a Brix refractometer:

The index of refraction (the complex number measure between the incidence ray and the refracted ray) for glucose (10% solution @ 20C) is 1.3477. For maltose it is 1.4068. [1.4068 / 1.3477 = 1.0438 or roughly 1.04 wort correction factor (WRI)].

As to the computations for correcting the presence of alcohol (ethanol) I can't find the corresponding reference. It has to do with Snell's Law, but I can't find the equation as it applies to the presence of alcohol in a maltose solution. Of course as home brewers we aren't usually bound by accuracies down to the third or fourth decimal. It's been my experience that a refractometer reading corrected to a nominal mid-range observation is at least as accurate as my ability to discern the meniscus in a hydrometer jar and correctly measure and compensate for temperature of the sample. At least down to two decimal points.

Brooo Brother

 

[VikeMan]

The index of refraction (the complex number measure between the incidence ray and the refracted ray) for glucose (10% solution @ 20C) is 1.3477. For maltose it is 1.4068. [1.4068 / 1.3477 = 1.0438 or roughly 1.04 wort correction factor (WRI)].

Nice explanation. One nit... the refractometers we use, i.e. "Brix" refractometers are referenced to sucrose and not glucose (because a Brix is by definition 1 gram of sucrose in 100 grams of solution). The difference in refraction is, however, negligible.

 

[Brooothru]

Nice explanation. One nit... the refractometers we use, i.e. "Brix" refractometers are referenced to sucrose and not glucose (because a Brix is by definition 1 gram of sucrose in 100 grams of solution). The difference in refraction is, however, negligible.

Right again. I saw the error but decided not to edit since the RI's are essentially the same, and most people (me included) mistakenly use the two almost interchangeably.

 

[iamwhatiseem]

Well.... it looks the problem is the grains.
Just sent a message to the HBS who supplied the grains.
I pitched new yeast yesterday around 4pm... 24 hours later... nothing. The new yeast has done nothing.
I am going to guess that the grains were terribly crushed, or they forgot to crush parts of the bill... I don't know. But it is now roughly 2.8% ABV beer, which it should be between 4.7% - 5.2% according to Beersmith.
I mashed as I always do, many-many times before - never happened before.

 

[iamwhatiseem]

Well this is just crazy!!.... I am sitting here in the living room and I thought I heard water dripping... what the??
So I go towards where I am hearing it... it ain't water dripping... it's this beer!!
It is fermenting away like there is no tomorrow. Nice looking, creamy krausen... what in the world?
Absolutely nothing has changed. I have not touched it. We almost went ahead and bottled this Sunday...well thank goodness we didn't!
10 days go by and just like that it started fermenting again.