Low OG and high FG

[jamie.forde94]

Hi All,

To be honest I'm just looking for anyone to ease my mind!

I've been brewing solidly now for over a year and the only thing that has gone wrong so far is that the water in Ireland does not suit some of the styles I am shooting for. My residual alkalinity is 207ppm.

Now I recently brewed a pale ale, however it came out quite dark, yeasty and a somewhat soapy sort of taste. I put this down to not clearing my beer adequately before bottling and also the alkalinity in my water.

So fast forward to my most recent brew, same grain bill just different hop additions. My system was also the same, a BIAB with sparge, however I did tweak my water profile. I added CRS (carbonate reducing solution), to bring down my alkalinity. This went into my mash water and sparge water. I also added a teaspoon of gypsum to the mash.

When racking this to my fermentation vessel, I took a gravity reading - I was looking for 1.059 but got 1.045ish. Pitched Nottingham yeast, threw on the blow off tube and waited. After 6 or so hours I was having a vigorous fermentation and it didnt really calm down until day 2-3. After this I added my dry hops, but also added geletin this time for better clarity.

I bottled yesterday, aroma was fantastic, beer was a lovely yellow and it was very clear so I was delighted. Didnt take an FG until after it had been bottled, because it was the exact same as my previous brew. When I did the FG was 1.035ish!

What is the likelihood my hydrometer is faulty?

If it's not faulty I will just have to turn this into a positive and learn something! How can a very visibly similar fermentation yield that high an FG.

TIA

 

[VikeMan]

What is the likelihood my hydrometer is faulty?

I can't think of a reason for a hydrometer to read too low, and then too high a few days later. But if you suspect your hydrometer may be off, see what it reads in plain water.

Also, make sure you are correcting your readings for temperature. (For example, what was the temperature of the wort when you racked to the fermenter, i.e. when you got the reading that was much lower than you expected?)

 

[balrog]

and check your thermometer used for measuring mash temps

 

[schmurf]

The hydrometer sample after bottling, was it prior to adding priming sugar?

 

[jamie.forde94]

I can't think of a reason for a hydrometer to read too low, and then too high a few days later. But if you suspect your hydrometer may be off, see what it reads in plain water.

Also, make sure you are correcting your readings for temperature. (For example, what was the temperature of the wort when you racked to the fermenter, i.e. when you got the reading that was much lower than you expected?)

I've tested the hydrometer in plain water and getting readings of/between 1.005 and 1.008.

Temperature was around 20°C when I took the FG and around 22°C when taking the OG.

and check your thermometer used for measuring mash temps

I am using a Peco Boiler with a temperature regulator that I set to 60°C. After that I just let it do its work, with the occasional stir of the mash.

The hydrometer sample after bottling, was it prior to adding priming sugar?

This is something that never dawned on me - it was after adding the priming sugar of 100g. Would this have a noticeable influence on readings?

 

[VikeMan]

This is something that never dawned on me - it was after adding the priming sugar of 100g. Would this have a noticeable influence on readings?

Yes, but how much depends on the volume of beer. What was the volume you added the sugar to?

 

[rburrelli]

I've tested the hydrometer in plain water and getting readings of/between 1.005 and 1.008.

Temperature was around 20°C when I took the FG and around 22°C when taking the OG.


I am using a Peco Boiler with a temperature regulator that I set to 60°C. After that I just let it do its work, with the occasional stir of the mash.


This is something that never dawned on me - it was after adding the priming sugar of 100g. Would this have a noticeable influence on readings?

Certainly would. Carbonation will give a false reading. You need to make the beer “flat” then take a reading.

 

[Tobor_8thMan]

Hydrometers are calibrated at 60F or 68F (15 to 20C). Was an hydrometer adjustment made for the sample temp?

Is something, CO2 bubbles, pushing up the hydrometer reading?

 

[VikeMan]

Hydrometers are calibrated at 60F or 70F (15 to 21C).

I've never seen a hydrometer calibrated to 70F. Perhaps you meant 68F (20C), which is very common.

 

[VikeMan]

Certainly would. Carbonation will give a false reading. You need to make the beer “flat” then take a reading.

@jamie.forde94 how long after bottling did you take that FG reading?

 

[Tobor_8thMan]

I've never seen a hydrometer calibrated to 70F. Perhaps you meant 68F (20C), which is very common.

Yes, good catch. My mistake.

 

[9Kegs]

You said: I've tested the hydrometer in plain water and getting readings of/between 1.005 and 1.008
When testing try to use distilled water and you should be right on 1.000

 

[VikeMan]

You said: I've tested the hydrometer in plain water and getting readings of/between 1.005 and 1.008
When testing try to use distilled water and you should be right on 1.000

To the accuracy of our hydrometers, tap water gravity is the same as distilled.

 

[jamie.forde94]

Yes, but how much depends on the volume of beer. What was the volume you added the sugar to?

It was 100grams in 16 litres. I took the sample just after putting the cap onto the last bottle.

I've purchased a refractometer for future readings so I have something to compare my hydrometer readings too- I was not aware temp was important when using a hydrometer.

 

[schmurf]

This is something that never dawned on me - it was after adding the priming sugar of 100g. Would this have a noticeable influence on readings?

100 gram sugar in 16 litre wouldn't raise the gravity that much, if the gravity was somewhere in the 1.010 - 1.020 range.

 

[jamie.forde94]

100 gram sugar in 16 litre wouldn't raise the gravity that much, if the gravity was somewhere in the 1.010 - 1.020 range.

No worries, guess I will just have to play the waiting game and see how the beer turns out and if the readings were incorrect.

Just for the future, if the readings were correct - what would have made the SG move so slowly? Compared to my other brews - could it be the CRS?

Thanks everyone for the responses!

 

[VikeMan]

It was 100grams in 16 litres.

So, that sugar would have raised your FG by a little over 2 points, i.e. .002 (regardless of what it was to start).

I took the sample just after putting the cap onto the last bottle.

So, there was no carbonation from priming sugar influencing the reading. Just the sugar itself.

Just for the future, if the readings were correct - what would have made the SG move so slowly? Compared to my other brews - could it be the CRS?

We know the reading couldn't have been correct, based on your readings with plain water. But the only way all of this makes any sense (IMO) is that either/or/both...
A) Your OG reading was not really taken around 22C, i.e the temp was much higher.
B) The yeast had not finished attenuation...you added gelatin (which if effective, removed the yeast) and bottled too soon.

I've never heard of CRS.

 

[jamie.forde94]

So, that sugar would have raised your FG by a little over 2 points, i.e. .002 (regardless of what it was to start).



So, there was no carbonation from priming sugar influencing the reading. Just the sugar itself.



We know the reading couldn't have been correct, based on your readings with plain water. But the only way all of this makes any sense (IMO) is that either/or/both...
A) Your OG reading was not really taken around 22C, i.e the temp was much higher.
B) The yeast had not finished attenuation...you added gelatin (which if effective, removed the yeast) and bottled too soon.

I've never heard of CRS.

Thanks very much, I'll make sure to leave it for a bit longer the next time.

Its carbonate reducing solution, it seems to be a product sold in the UK and Ireland, because my wifes brother in law from New York hasn't heard of it either. Distilled water isn't as readily available here it seems, so this seems to be the alternative to reduce the alkalinity of water.

Thanks for all the help