Help! with gravity calculation. math is hard

[HB_ATL73]

Appreciate the conversation on the calculations- helps a lot

 

[lump42]

Third batch- not even close... 3rd BIAB yes. Also, yes triple scale cheap hydrometer- so given the calculations I'm sure it would be easy to miss .001-.002 points

I misread that part, no offense intended. My visions bad enough that I always struggled reading the triple scales. I finally broke down and bought the narrow range hydrometers, just so I can read them easier.

 

[lump42]

Went back and re-read.

In the end the difference is so small that the whole exercise is just a math problem to solve.

IMO, the difference is well within the margin of error of just READING the hydrometer. Unless of course you have a very accurate narrow range hydrometer.

That's all assuming that the hydrometer is calibrated properly (triple-scale or narrow-range).

PSA:check the calibration of your equipment. The more you know!

 

[balrog]

I misread that part, no offense intended. My visions bad enough that I always struggled reading the triple scales. I finally broke down and bought the narrow range hydrometers, just so I can read them easier.

Love my 1.040 max bottling hydrometer and narrower range OG hydrometer (can't remember the range now). I still hve trouble reading them tho.

 

[lump42]

Love my 1.040 max bottling hydrometer and narrower range OG hydrometer (can't remember the range now). I still hve trouble reading them tho.

Agreed, I had a nice set from Northern Brewer, but after 6 years I broke my mid-range that I used all the time (1.000-1.060) that had .0005 graduations. I still struggle a bit, but if I squint hard enough I can count the little lines. I was always told getting old would suck...I just didn't know it was going to be this soon.

 

[balrog]

I started having to use readers at about 35 and that was 25 years ago.
I have both the Williamsbrewing ones, "bottling" .0005 marks, 1.000-1.040; and "narrow range" 1.000-1.100, awesome.

 

[HB_ATL73]

I misread that part, no offense intended. My visions bad enough that I always struggled reading the triple scales. I finally broke down and bought the narrow range hydrometers, just so I can read them easier.

I knew none was intended. I need to get myself a narrow range one I struggle myself with reading a triple scale

 

[Gnomebrewer]

I can see if you are looking for the total from the start of each step = 1.082----- math.. not an actual number that you could measure with a hydrometer.

Actually it's 1.083. 1.082 was using 1.012 as the gravity of the starter.
If, in a couple of weeks time, the beer was at 1.015. What is the ABV? Using Brewers Friend calculator it's 8.9%. We couldn't calculate that if we didn't know the OG of all contributing worts. If the wort without the starter was used for calculations (4.75 gal at 1.090 watered down to 5 gal gives a 1.0855 wort), the ABV would be calculated at 9.6% - quite a big difference. Using 1.082 (which is about what the hydrometer is likely to measure from the 'actual' combined pre-ferment beer) the ABV would be 8.8% - not significantly different to the first calculation and within the error margin of normal measuring equipment. I often add a 3L 'vitality' starter to 20L/5 gal Lager batches though - the difference becomes much greater with the bigger starter so becomes more important to know the calculated OG of all worts.

 

[kh54s10]

So we have a calculation of 1.083 if the starter pre-ferment gravity is taken and 1.082 if not. I don't know where your 1.0855 number comes from since a starter was added.

1.083 and 5 gallons with 1.015 as a FG = 8.93 ABV
1.082 and 5 gallons with 1.015 as a FG = 8.79 ABV

All this is within the window of error of just reading a hydrometer.

 

[lump42]

I started having to use readers at about 35 and that was 25 years ago.
I have both the Williamsbrewing ones, "bottling" .0005 marks, 1.000-1.040; and "narrow range" 1.000-1.100, awesome.

I broke my middle range 1.000-1.070 one after 6 years. I was looking for a direct replacement and could only find them from lab suppliers who were charging $50+ ea. Luckily found the 1.000-1.100o unit at Williams as well. It's been a sigh of relief to put the triple scale back into storage.

 

[balrog]

I broke my middle range 1.000-1.070 one after 6 years. I was looking for a direct replacement and could only find them from lab suppliers who were charging $50+ ea. Luckily found the 1.000-1.100o unit at Williams as well. It's been a sigh of relief to put the triple scale back into storage.

<don't tell anyone but I still use my original, the expanded range, and anything else I can measure with when it comes time to measure...yes, it is a disease>