Problems hitting final gravity

[CoastalEmpireBrewery]

So it's been quite some time since I've been on here. Here lately I've been putting more of an emphasis on hitting my final gravity mark to produce a nice clean beer that's not overly sweet.

So just for some background I brew on a Sabco V350MS. The latest brew was a light American lager. I'll add the recipe to make it easier to help identify any issues.

Recipe:
6lb- 2row
2lb- flaked maize
.5lb- carapils
White labs American lager yeast (2L Starter)

I did a single step mash which was kept at 148°F for approximately 70 min and then boiled for an hour. It was then placed in a regulated fridge at 55°F.

My O.G. reading was a little higher than I expected at 1.063... My F.G. after two weeks was 1.035.. Which to me is extremely high. I used a .5 micron air stone, yeast was in a 2L starter.

Only thing I can think of is that possibly going up on the temp to 150°F.. I cannot tell if my issue is excessive unfermentables or yeast just stopping. Anyone have any ideas?

 

[Yooper]

I have several ideas! But the first is to confirm that you are NOT using a refractometer and using a hydrometer that reads 1.000 in pure water?

If you're using a refractometer, run and take a hydrometer reading and get back to us with the reading.

 

[cyanmonkey]

Yes, that's extremely high.

I'd question yeast health. 150 isn't terribly high and should produce a drier beer.

Have you tasted it?

 

[didinho]

did you place the beer directly in te fridge? I usually let the yeast consume the oxigen at room temperature, and put at lager fermentation temp when it starts bubbling.
anyway, 1065 OG is quite high for a lite lager...

 

[CoastalEmpireBrewery]

I set both the yeast starter and the wort in the fridge and let them drop down to the temp then I add the yeast... I've been using a refractometer... Had a bad spell of breaking hydrometers so I went to that.. I haven't tasted it yet. I just moved it to a keg last night so probably in a couple weeks

 

[CoastalEmpireBrewery]

I've made this recipe before and it turns out amazing.. I can not keep a keg around when my neighbors find out that I made it and it's ready

 

[Bellybuster]

.. I've been using a refractometer...

As Yooper already pointed out, using a refractometer in already fermented wort will not give you the correct reading.
Your 1.035 is actually closer to 1.017

 

[augiedoggy]

Yes I second refractometers are only accurate when their is no alcohol present in the liquid.

 

[Yooper]

Yes I second refractometers are only accurate when their is no alcohol present in the liquid.

Right. There are calculators out there that can give you a corresponding FG, but in my experience they aren't that accurate.

Sean Terrell has one on his site.

A refractometer is great for prefermentation readings, but since alcohol skews the refraction of light, they aren't even close to accurate once fermentation starts.

Your beer isn't 1.035- it's probably half that or maybe even less.

http://seanterrill.com/2012/01/06/refractometer-calculator/ is the link to guestimate the probable FG.

 

[pricelessbrewing]

For what it's worth I did 10 brews comparing Sean terrills correction to a standard triple scale hydrometer. After finding my wort correction factor of 1.04 and using his FG correction tool it was always within half a gravity point of each other, which is well within the error of using a hydrometer for a standard trippel scale hydro.

 

[CoastalEmpireBrewery]

That is definitely possible. The beer doesn't taste sweet at all. I think I may increase to 150°F (instead of 148°F) to give maybe a little more body

 

[Yooper]

For what it's worth I did 10 brews comparing Sean terrills correction to a standard triple scale hydrometer. After finding my wort correction factor of 1.04 and using his FG correction tool it was always within half a gravity point of each other, which is well within the error of using a hydrometer for a standard trippel scale hydro.

Yes, but you took the time to determine your wort correction factor- without doing that (most people don't, even if they are instructed to), it just isn't going to be all that close.

 

[Calder]

For what it's worth I did 10 brews comparing Sean terrills correction to a standard triple scale hydrometer. After finding my wort correction factor of 1.04 and using his FG correction tool it was always within half a gravity point of each other, which is well within the error of using a hydrometer for a standard trippel scale hydro.

It is still only accurate for the beers that you used for your calibration. If you make one with a higher gravity, or use a higher mash temperature to create more complex sugars, you may find it is no longer that accurate.

Or a simpler brew, lower gravity, or more fermentable wort.

The refractometer 'tool' or calculator is purely based on empirical data. Anything outside of the data used for the 'tool' will result in inaccuracies.

OK ... then one should use a wide spectrum for the 'tool' calibration ...... but that then just results in an an average result, where all results are subject to question.

Yes, you can get decent results, but I question anyone claiming it to be accurate within .001 of hydrometer readings for all beer styles.

 

[pricelessbrewing]

It is still only accurate for the beers that you used for your calibration. If you make one with a higher gravity, or use a higher mash temperature to create more complex sugars, you may find it is no longer that accurate.

Or a simpler brew, lower gravity, or more fermentable wort.

The refractometer 'tool' or calculator is purely based on empirical data. Anything outside of the data used for the 'tool' will result in inaccuracies.

OK ... then one should use a wide spectrum for the 'tool' calibration ...... but that then just results in an an average result, where all results are subject to question.

Yes, you can get decent results, but I question anyone claiming it to be accurate within .001 of hydrometer readings for all beer styles.

My largest discrepancy was a Belgian trippel 7.6% difference of 0.004 and an imperial stout 9.2% 0.0004. Everything else was within 0.0002-0.0003 which is more than good enough for me. I no longer bother with my hydrometer.

The trippel had some sucrose addition which probably messed with it slightly, if you care about a half gravity point then you should probably get some short range hydrometers.