Two hydrometers, two different readings..

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

discokid2k

Well-Known Member
Joined
May 10, 2010
Messages
176
Reaction score
4
Location
Austin
I hav ebeen chasing an efficiency issue for awhile now and I have literally examined every aspect of my brew days. I finally bought a new hydrometer to see if that may help me find the missing points I am consistently losing somewhere in my brew schedule and would you look at that... Hydrometer on the left is the old one, on the right in the new one. The temp of the beer was 72*, both are calibrated at 60*. A solid 6, almost 7 point gap from new to old. The FG of the beer should be a 1.011 and we are off by one point according to the new hydrometer.

Has my problem, my white efficiency whale seriously been a simple $3 solution???:drunk: Tomorrow's brew day will answer this. Any thoughts? I was pretty surprised to see these results.

IMG_1391.jpg
 
It is not uncommon for the paper inside to come loose and move. But as stated use distilled or reverse osmosis water and it should read 1.000.
 
After taking a reading with water you can add (if it reads low) or subtract (if it reads high) the measured error from all future readings. I have never had a hydrometer which read 0 for water. I always have to adjust. My current hydrometer reads 1.003 with water at 60F. So, I subtract 3 gravity points from all readings.
 
I have done the water reading on both. The one on the left is off by 4pts in distilled water. That does not account for the almost 7pt difference in my gravity reading here though. I have been correcting my readings by 4 but now I am not so sure that is a perfect adjustment.
 
Try a two-point calibration.
http://***********/stories/projects...rate-your-hydrometer-and-fermenter-techniques
 
I have done the water reading on both. The one on the left is off by 4pts in distilled water. That does not account for the almost 7pt difference in my gravity reading here though. I have been correcting my readings by 4 but now I am not so sure that is a perfect adjustment.

If the one on the left is off by 4 points in one direction, and the one on the right is off by 3 points in the other direction, that would explain the 7 points difference.

-a.
 
My hydrometer is high by .003 in RO water. Since I bought it, I have been adjusting by that .003 and having a real problem hitting my OG. I recently did the two point calibration as described in BYO and found that it is right on the money at 1.057. So, at least for my hydrometer, the calibration adjustment is not consistent across the range from 0 to typical wort sg.
 
If the one on the left is off by 4 points in one direction, and the one on the right is off by 3 points in the other direction, that would explain the 7 points difference.

-a.

The right hydrometer is perfect in water. The one on the left is -.04 pts in distilled water. The 7 pts difference remains a mystery. My solution is to try the two point calibration that was suggessted and after that, I may toss the one on the left. I am going to do one full brew session before I throw anything away just to be 100% sure. Like I said in the original post, I have been running down the efficiency issue for awhile. I have tried everything except 1) a new hydrometer (obviously am on that one now) and 2) my own mill. But I think I found the issue, the hydrometer. The picture is very telling indeed.
 
Try a two-point calibration.
http://***********/stories/projects...rate-your-hydrometer-and-fermenter-techniques

Going to try this one today! The hydrometer on the left is pretty old, a few years at least so I won't be hurting to lose it.
 
One of the scales is printed wrong. That would be the only way they would be different at start and finish barring user error reading the scale.

Well, the picture is posted for all to see and even with the .04 correction for hydrometer on the left, it still sits at 1.008. The new hydrometer sits right above 1.010 and my FG was supposed to be 1.011. Aside from user error which is posted for all the world to see, there seems to be no explanation for this. The hydrometer on the left has been spot on before so I dont believe it is a printing error. I think the paper has shifted over time personally but I mainly just wanted everyone elses input. I have kept detailed notes of my last dozen brew days or so and have been frustrated with the missing efficiency points. I will just have to brew more to see if I am right....:rockin:
 
In regards to your FG; the FG predicted by software or formulas is just a prediction. Actual results can and do vary significantly. FG depends on many a factors. Most yeasts have a 5-10% range for predicted attenuation.

Bottom line: you can't judge your hydrometer accuracy based on the FG measurement. The only way to judge your hydrometer is with water (1.000 SG) or with a known mixture of malt extract or sugar with a known volume of water.
 
Well, the picture is posted for all to see and even with the .04 correction for hydrometer on the left, it still sits at 1.008. The new hydrometer sits right above 1.010 and my FG was supposed to be 1.011. Aside from user error which is posted for all the world to see, there seems to be no explanation for this. The hydrometer on the left has been spot on before so I dont believe it is a printing error. I think the paper has shifted over time personally but I mainly just wanted everyone elses input. I have kept detailed notes of my last dozen brew days or so and have been frustrated with the missing efficiency points. I will just have to brew more to see if I am right....:rockin:

Was not making a judgement. I read the issue as the two hydrometers reading at different point differences at start and finish.
 
My hdyro is off too....calibrating it in filtered water it read 4 points low, so I just adjust. As far as your other discrepancy, who knows?? As a solution you could buy another hdyro, and take the averages out of three:D
 
In regards to your FG; the FG predicted by software or formulas is just a prediction. Actual results can and do vary significantly. FG depends on many a factors. Most yeasts have a 5-10% range for predicted attenuation.

Bottom line: you can't judge your hydrometer accuracy based on the FG measurement. The only way to judge your hydrometer is with water (1.000 SG) or with a known mixture of malt extract or sugar with a known volume of water.

I have been tracking an extraction efficiency issue. My brewhouse efficiency comes out around 75% usually, which is good from what I understand. But I have noticed the OG's dropping from the software I use (Hopville) but again, hopville bases the % off of mash efficiency..I think. I just bought the new hydrometer to see the results and was kind of shocked at the variance between the two.
 
Was not making a judgement. I read the issue as the two hydrometers reading at different point differences at start and finish.

Oh no worries. I appreciate everyone's input. My overall brewhouse efficiency is in a decent range but I find my self irritated that I am not hitting my OG's spot on. I have read that extraction efficiency is not as important as overall brewhouse efficiency but I cannot help but take notes and try to analyze the issue.

My main frustration is the variance between the two hydrometers? Either way, I am within three points of expected FG so I guess I should not worry but I am all about details and procedure, so I cannot help but get irritated by it. I dothink that the paper inside has slipped over time. As stated, I have tried all of Flyguy's tip in his sticky for effciency so when I miss my OG AND I have tried every tip, I get :mad:

Still, for a $2 tool, how much accuracy can I expect??:drunk:
 
My hdyro is off too....calibrating it in filtered water it read 4 points low, so I just adjust. As far as your other discrepancy, who knows?? As a solution you could buy another hdyro, and take the averages out of three:D

That is actually not a bad idea. I have tested both hydro's in water and one is spot on, the other is -.04pts. Testing in a solution say, four or five times each and averaging the results is a great test. I will give that a shot.
 
That is actually not a bad idea. I have tested both hydro's in water and one is spot on, the other is -.04pts. Testing in a solution say, four or five times each and averaging the results is a great test. I will give that a shot.

Or you could just RDWAHAHB :mug:
 
Or you could just RDWAHAHB :mug:

Ha! It is exactly the RDWHAHB mantra that caused me to start taking better notes! I keep my drinking to a minimum on brew days now:drunk: At least on beers that I am trying to perfect:D
 
Reminds me of a saying I once heard: "A man with one watch knows what time it is, a man with two is never quite sure."

I guess other than doing some two point calibration or buying a third and hoping there is agreement between two of them I'm not sure what else you could do.... Maybe buy a refractometer?
 
Reminds me of a saying I once heard: "A man with one watch knows what time it is, a man with two is never quite sure."

I guess other than doing some two point calibration or buying a third and hoping there is agreement between two of them I'm not sure what else you could do.... Maybe buy a refractometer?

Ha! So true...the refractometer is on my list. I brewed tonight and I had better results doing a few different tricks. 1st, I re-crushed my grain using a bowl and mallet...just to be extra sure. Then I added my full sparge to my mash out to hopefully thin the sugars a little. Also cut nearly 1/2 gal out of calculation just to be sure I wouldn't pull too much water (also added a little over 1qt to cool my mash before starting timer).

Old hydrometer read 1.040 and new read 1.044. Temp correction (@77*) gives me a 1.046 and only -7pts from my expected OG of 1.053. Brewhouse efficiency today rose by 10%, up to an 85%. Not to shabby:D
 
That is actually not a bad idea. I have tested both hydro's in water and one is spot on, the other is -.04pts. Testing in a solution say, four or five times each and averaging the results is a great test. I will give that a shot.

A 0.04 pt difference in water and a 0.07 difference in wort means the slopes of the two hydrometers are not the same. Take a third reading after adding a teaspoon of sugar to your wort sample, plot the results on a graph, then throw away the hydrometer on the left.:drunk:
 
One of the scales is printed wrong. That would be the only way they would be different at start and finish barring user error reading the scale.

I have been thinking about this and I'm not certain that it is true. The variation of buoyancy with density is linear. The relationship between the density of the wort and the vertical movement of the hydrometer is not linear. As the hydrometer sinks further with lower gravity more of the stem is under the surface and so the buoyancy force goes up. Is the diameter of the stem tapered to counter-act this or is the scale non-linear? I have no idea. If it is isn't, then I would expect the hydrometers to be more accurate at higher gravities when less of the stem is under the surface. I tried a two-point calibration which bore this out. Of course it is entirely possible I flubbed something up.
 
Back
Top