Incohrent Brix readings of 2 IPAs

[lolcats]

Hey guys,

Another noob thread for you.

I brewed these 2 IPAs 2 Saturdays in a row.

-Left is a Chinook/Citra IPA with an OG of 1.055. This one was brewed on the first Saturday. I dry hopped it 6 days after (last Friday).

-Right is a Light Munich/Citra Smash IPA with an OG of 1.050. This one was done last Saturday.

So yesterday I took Brix readings for both (left has been fermeting for nine days, right for 2.5). Left has a brix reading 8.2 and right of 8.6.

Using Sean Terril's FG calculator, thats a 1.016 on the left and 1.018 on the right. I was expecting lower on the left, since that's only a 69% attenuation and it's been fermenting for 9 days already.

Fermentation temps have been constant around 68F. Pitched exactly a half vial of White Labs California ale yeast in both. Both 1 Gallon batches.

Any advice?

 

[Chris_Primavera]

Need some more information here

All grain or Extract?
Mash temperature?

Might have had less yeast in one "half vial" not sure how you divided it.

 

[lolcats]

Both all grain. Tried to keep the mash temps in the lower 150s (using a kettle).

I split the vial by eye, but if anything think a pitched more in the first than in the second.


I also used tin foil on the left batch for the first 6 days then switched to airlock for dry hopping.

 

[Yooper]

Even with the correction software, sometimes those readings are inaccurate. Well, for me, I've never had one actually be accurate at all, but for others they seem ok from what I've read.

Don't worry about it. It's done when it's done, whatever the FG reading is, and those readings are not worrisome even if accurate.

 

[lolcats]

Yeah I agree.

The only thing, is that the first one is dry hopping since Friday and should therefore need to be cold crashed / bottled in a few days.

 

[doug293cz]

If you are not comfortable with the accuracy of corrected refractometer readings, you can still use them to monitor for completion of fermentation. When the readings are stable for a few days, you are done. You can then use a hydrometer (before adding priming sugar) to get an accurate FG. The tiny sample volumes required by the refractometer are a big benefit for small batches, when sampling multiple times.

Brew on

 

[lolcats]

If you are not comfortable with the accuracy of corrected refractometer readings, you can still use them to monitor for completion of fermentation. When the readings are stable for a few days, you are done. You can then use a hydrometer (before adding priming sugar) to get an accurate FG. The tiny sample volumes required by the refractometer are a big benefit for small batches, when sampling multiple times.

Brew on

That's exactly what i'll be using my refractometer from now on. That and determining pre boil gravity.

Actually I just took another reading today and the Brix reading dropped from 8.2 to 7.5 so 1.016 to 1.014 within 24 hours. Clearly the fermentation is not done. Was expecting it to have been done by now after 10 days. I feel better though, the apparent attenuation is exactly 75% right now.

I should have taken a refractometer reading before dry hopping i guess...

 

[lolcats]

Just pulled a new Brix reading for both 8 for the left one and 7.8 for the right one.

I don't understand. I measured 7.5 yesterday and 8 today. I must have screwed something up yesterday.

I also notice that I have to recalibrate the refractometer very often. Temps are pretty much the same every time a recalibrate. So don't really know whats going on.

 

[Yooper]

Just pulled a new Brix reading for both 8 for the left one and 7.8 for the right one.

I don't understand. I measured 7.5 yesterday and 8 today. I must have screwed something up yesterday.

I also notice that I have to recalibrate the refractometer very often. Temps are pretty much the same every time a recalibrate. So don't really know whats going on.

I know that alcohol skews the readings, so I don't trust my refractometer once fermentation has started. You can wait longer, and just assume it's done I guess.

 

[lolcats]

I just pulled a sample to check the hydrometer reading...

1.020

 

[Yooper]

I just pulled a sample to check the hydrometer reading...

1.020

It's definitely not clear, so maybe it's still fermenting. No worries, just give it time to clear and check it then.

 

[lolcats]

It was very clear before i dry hopped the thing with 0.8oz.

It's been 11 days now and just 62% attenuation.

I guess i've been struck with the 1.020 curse.

In any case just proves that Brix readings + correction factor = bs

 

[Singletrack]

Nah, you're okay with the refractometer. Yeah, you need to calibrate all the time, and the readings aren't perfect, but you really just need a sense for the approximate OG and FG, and you will get that with your refractometer. If you were brewing 1 bbl batches, than you could waste a few hydrometer samples. It looks like your batch size is too small to waste any samples. Give the beer enough time, take a refract for "sense" purposes, and enjoy the beer.

Nothing wrong with the other advice you received, but wanted you to know there are nuts out there/here who never use a hydrometer and still make beer that only occasionally causes an uncontrollable gag reflex.

 

[lolcats]

Nah, you're okay with the refractometer. Yeah, you need to calibrate all the time, and the readings aren't perfect, but you really just need a sense for the approximate OG and FG, and you will get that with your refractometer. If you were brewing 1 bbl batches, than you could waste a few hydrometer samples. It looks like your batch size is too small to waste any samples. Give the beer enough time, take a refract for "sense" purposes, and enjoy the beer.

Nothing wrong with the other advice you received, but wanted you to know there are nuts out there/here who never use a hydrometer and still make beer that only occasionally causes an uncontrollable gag reflex.

I agree, but there's a big difference between 1.016 and 1.020

That's more than approximate IMO

 

[doug293cz]

I agree, but there's a big difference between 1.016 and 1.020

That's more than approximate IMO

Are you pressing down on the cover glass to expel excess solution prior to taking a reading? Do you make sure you don't have any bubbles in the liquid film on the prism?

Brew on

 

[lolcats]

Are you pressing down on the cover glass to expel excess solution prior to taking a reading? Do you make sure you don't have any bubbles in the liquid film on the prism?

Brew on

Yes thats exactly what I do, I press down, lift it back up and drop it back down. I feel like it gives a clear distinctive line that way.

Actually I just realized this morning how important the temperature of the calibration water is. I would take water from my sink fosset and try to get a medium temperature water. Compared that with water thats been in the cooler at the same temperature as the carboys. And the difference was 0.5 Brix. So I guess that's the reason why I get random readings.

However it does't explain why I read 7.6 Brix (this morning) and the hydrometer reading is 1.020..

 

[singybrue]

I'm pretty sure you need to calibrate the refractometer with distilled water. That's what I use.
That could explain varible readings.

 

[doug293cz]

Yes thats exactly what I do, I press down, lift it back up and drop it back down. I feel like it gives a clear distinctive line that way.

Actually I just realized this morning how important the temperature of the calibration water is. I would take water from my sink fosset and try to get a medium temperature water. Compared that with water thats been in the cooler at the same temperature as the carboys. And the difference was 0.5 Brix. So I guess that's the reason why I get random readings.

However it does't explain why I read 7.6 Brix (this morning) and the hydrometer reading is 1.020..

I'm not so sure about the lifting it back up and dropping it back down part. I've never seen that done or suggested anywhere.

Brew on

 

[hannibalmdq]

I'm pretty sure you need to calibrate the refractometer with distilled water. That's what I use.
That could explain varible readings.

Depends on your water. Distilled and tap read the same for me.

 

[hannibalmdq]

Yes thats exactly what I do, I press down, lift it back up and drop it back down. I feel like it gives a clear distinctive line that way.

Actually I just realized this morning how important the temperature of the calibration water is. I would take water from my sink fosset and try to get a medium temperature water. Compared that with water thats been in the cooler at the same temperature as the carboys. And the difference was 0.5 Brix. So I guess that's the reason why I get random readings.

However it does't explain why I read 7.6 Brix (this morning) and the hydrometer reading is 1.020..

It also important to note that a refractometer is measuring the index of refraction of light through the sample. Suspended particulate can skew the reading. Mine always reads a bit low while the yeast is still in suspension or just after dry hopping. After the solution has cleared, I've never had an issue getting a correct reading.

For what it's worth, a properly calibrated refractometer using Sean Terril's simlified cubic for Brix to SG conversion is at least as accurate as a .002 marked hombrew hydrometer.

I still take hydrometer readings every 5 or 10 batches just for sanity, but my corrected refractometer reading has never been off from the hydrometer reading by more than the resolution of either instrument.

I kind of suspect that the refractometer gets a bad rap because of QC control. I think some people get poorly made devices and some of us get well made ones. In the last 2 years I think I've had to correct the calibration on mine once, and that time it was barely off 0 with distilled water.

 

[lolcats]

It also important to note that a refractometer is measuring the index of refraction of light through the sample. Suspended particulate can skew the reading. Mine always reads a bit low while the yeast is still in suspension or just after dry hopping. After the solution has cleared, I've never had an issue getting a correct reading.

For what it's worth, a properly calibrated refractometer using Sean Terril's simlified cubic for Brix to SG conversion is at least as accurate as a .002 marked hombrew hydrometer.

I still take hydrometer readings every 5 or 10 batches just for sanity, but my corrected refractometer reading has never been off from the hydrometer reading by more than the resolution of either instrument.

I kind of suspection that the refractometer gets a bad rap because of QC control. I think some people get poorly made devices and some of us get well made ones. In the last 2 years I think I've had to correct the calibration on mine once, and that time it was barely off 0 with distilled water.

Great advice

Do you think the hop haze can also impact the refractometer reading?

I know hops don't affect a hydrometer reading, but didn't think at all it could possibly affect the refraction of light

 

[hannibalmdq]

Great advice

Do you think the hop haze can also impact the refractometer reading?

During the first few days of dry hopping, yes. I've seen it read a few points low. After the bulk of the hop particulate has settled out, I've not noticed any deviation between instruments soley caused by the resulting haze.

 

[lolcats]

The thing is a dry hopped before fermentation was done (at 6 days), so the dry hops is (still) not falling down to the bottom and keeps coming back up and creating a green foamy cake at the top.

Nailed it, that's the reason why i'm reading low Brix when the real gravity is still high. Learned the lesson now... Don't use a refractometer after having dry hopped to determine FG.

Also, could my grain bill be the reason why my fermentation is staying pretty high?

80% 2 row
8% german pilsner
7% carapils
5% crystal caramel 40

i know that carapils and crystal have less fermentable sugars...

 

[hannibalmdq]

The thing is a dry hopped before fermentation was done (at 6 days), so the dry hops is (still) not falling down to the bottom and keeps coming back up and creating a green foamy cake at the top.

Nailed it, that's the reason why i'm reading low Brix when the real gravity is still high. Learned the lesson now... Don't use a refractometer after having dry hopped to determine FG.

Also, could my grain bill be the reason why my fermentation is staying pretty high?

80% 2 row
8% german pilsner
7% carapils
5% crystal caramel 40

i know that carapils and crystal have less fermentable sugars...

12 percent specialty malt is not a large amount and you mashed it. When Caramel and Carapils are mashed they are almost as fermentable as base malt. The enzymes in the base malt will break down the longer chain sugars in the c40 and carapils during the mash. Reference link from the Mad Fermentationish.

Mash temp is the more likely culprit. If you're sure you didn't mash up towards the 160F range, I'd check your thermometer.

 

[lolcats]

Well I kettle mash

So it's true it's hard to keep a constant temp, especially the bottom of the kettle tends to be warmer then the top of the kettle.

I bring to water to 160F put the grains in, put lid on, flameout and check the temps every 15 minutes, usually if it's too low i turn to heat back on.

I may have overshot at one point but not over an extended period of time.

Thanks anyway

 

[lolcats]

Just to give a quick update the IPA is pretty much stabilized around 1.017 that had an og of 1.055.

I was suspecting my thermometer for ****ing up my mash temps. I calibrated it with boiling water and the water was boiling steadily with a temp of 206F instead of 212.

I think all noob brewers like me should calibrate their thermometer before brewing again. I was mashing without knowing in the 160F range instead of 152 or 154. Just enough to screw things up. People don't insist on this enough.

Nevertheless the flat beer tastes awesome just a tad sweet! Thank you Citra <3