the most accurate hydrometer reading is ??

SSBrew - 728
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.
cadarnell

cadarnell

Well-Known Member
Joined
Dec 8, 2010
Messages
545
Reaction score
56
Location
Bloomington In.
I have been doing all grain brewing for about 15 batches of beer now .. I do them in my kitchen, on my stove. I can only boil about 4 1/2 gallons of wort comfortably, so to make a full batch I have to top off .. I have been getting some conflicting hydro readings pre boil and after topping off .. I havent been doing a post boil, before topping off reading, beacuse that wort is so much harder to cool than pre boil ... I always think my after topping off reading should be 2 to 4 points higher based on my pre boil reading .. so which one is more accurate? ... I'm thinking the pre boil is but, I swear I mix that water in really, really well .. thoughts ?? .. :confused:
 
Are you accounting for temperature? The hydrometer should have a temperature value on it and you need to adjust for temperature. Most hydrometers are calibrated to yield the correct reading when the solution it is floating in is 60 degrees F.

This is an important thing people tend to overlook and could easily account for the variability you mention.
 
A hydrometer with a temp valve on it? never heard of that one. But it should read 1.000 in water @ 60F. Mine does,so I'm good. Check yours & see what it says.
 
Irrenarzt said:
Are you accounting for temperature? The hydrometer should have a temperature value on it and you need to adjust for temperature. Most hydrometers are calibrated to yield the correct reading when the solution it is floating in is 60 degrees F.

This is an important thing people tend to overlook and could easily account for the variability you mention.
Click to expand...

yea .. I cool the samples to 80 or a little lower and then take the reading .. then I type the numbers into brewing software to get my adjusted number.
 
Your pre-boil reading will be lower than your post-boil reading typically. But since you're adding water you are diluting back down. How much you dilute it depends on how much water you add.

So by "conflicting" do you mean your pre-boil is greater than or equal to your post boil reading?

As an example, say you get a pre-boil gravity of 1.042. Then you'll boil for 60 minutes or so and cool. Then you may be at 1.050. Then you're topping off with water (1.000) so you may be down to 1.044 or something like that. Really just making up numbers, but you get the idea of the up-down swing.

The gravity reading you care most about is what is going into your fermenter. i.e. your cooled post-boil reading.
 
AnthonyC said:
Your pre-boil reading will be lower than your post-boil reading typically. But since you're adding water you are diluting back down. How much you dilute it depends on how much water you add.

So by "conflicting" do you mean your pre-boil is greater than or equal to your post boil reading?

As an example, say you get a pre-boil gravity of 1.042. Then you'll boil for 60 minutes or so and cool. Then you may be at 1.050. Then you're topping off with water (1.000) so you may be down to 1.044 or something like that. Really just making up numbers, but you get the idea of the up-down swing.

The gravity reading you care most about is what is going into your fermenter. i.e. your cooled post-boil reading.
Click to expand...

yea .. I learned the math to figure out how many points I lose to topping off ... but the way I do it it's really pretty simple to figure ... if my pre boil is 4.5 gallons at 1.052 and I top it back up to 4.5 gallons post boil, I should be back at 1.052 by my math .. maybe I am just not mixing the water well enough .. or I am using bad math :confused:
 
Irrenarzt said:
Not valve, value
Click to expand...

Dang! my good glasses broke into several pieces a week ago,& I'm wearing my previous pair that are polarized. That,& middle age might be making me dyslectic.lolz. I just figure the temp adjustment if/when I really need to be picky. I'm not an AG'r,just steep now & then. But I could swear...new glasses needed...
 
I see. Didn't realize you were topping it off to pre boil volume.

Don't forget about wort shrinkage. If your pre boil volume you are measuring is at mash out temps it will be slightly less volume when cooled. Don't know if that will ne enough for your discrepancy.
 

Similar threads

Vladimir Kim
Low OG
Replies
6
Views
552
IslandLizard
IslandLizard
cayugalakebrewer
Aerating Partial Boil?
Replies
1
Views
208
hotbeer
hotbeer
PashMaddle
First brew day is on the books.
Replies
39
Views
2K
GoodTruble
G
N
Wort chilling and brew pot water volume
Replies
7
Views
532
Bobby_M
Bobby_M
A
Accurate OG readings with real fruit?
Replies
9
Views
451
Austin Willoughby
A
Brewer's Friend 300

Latest posts

Back
Top