Get your HBT Growlers, Shirts and Membership before the Rush!


Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Misreading between hydrometer and refractometer
Reply
 
LinkBack Thread Tools
Old 07-27-2014, 06:13 PM   #1
kenpotf
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2011
Location: mckinney, tx
Posts: 521
Liked 10 Times on 10 Posts
Likes Given: 4

Default Misreading between hydrometer and refractometer

All,

I've got a beer in the fermenter that BS says it should be complete around 1.017. The estimated original was 1.072, but I hit 1.062 (the style is within 10 points I believe for a Porter). So, in my notes, I wrote I had 1.062. I don't remember that day very well

Okay, I did a reading with a hydrometer last Thursday and it read 1.022. I had zero krausen, so I figured it would be done but left it. I measured on Friday night with a refractometer that gave me 10 brix. I measured this morning, and it's still sitting at 10 brix. The problem that I have is the converters online show that 10 brix is 1.040 which means I only went down 18 points. If I do another hydrometer reading today, should I call it done if I still get a 1.022 reading? Or should I try to warm the fermenter up or even repitch?

And does anyone know why I would have a discrepancy that large between the hydrometer and refractometer? I understand that the refractometers are better pre-fermentation, but I could've sworn the calculators were pretty accurate...

Thanks!

__________________
kenpotf is offline
 
Reply With Quote Quick reply to this message
Old 07-27-2014, 06:39 PM   #2
doug293cz
BIABer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2014
Location: Renton, WA
Posts: 420
Liked 84 Times on 66 Posts
Likes Given: 36

Default

Refractometers measure index of refraction of solutions. Since both sugar solutions and ethyl alcohol solutions have higher indicies of refraction than water, refractometers do not read correctly for mixed solutions of sugar and alcohol. (Well they do read index of refraction correctly, but the index of refraction is not simply related to the alcohol or sugar content as it is for unfermented wort.)

It is possible to get an estimate of sp gr of a mixed sugar/alcohol solution, if you know the sp gr of the original wort. Probably the best calculator to use is the one by Sean Terrill: http://seanterrill.com/2012/01/06/re...er-calculator/. Sean has done a significant amount of correlation between refractometer and hydrometer readings on mixed sugar/alcohol solutions.

Brew on

__________________
doug293cz is offline
pdxal Likes This 
Reply With Quote Quick reply to this message
Old 07-28-2014, 12:21 PM   #3
kenpotf
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2011
Location: mckinney, tx
Posts: 521
Liked 10 Times on 10 Posts
Likes Given: 4

Default

Thanks. I played around with that site, and according to it my fg should be around 1.020. I called it at 1.025 and put the vanilla bean in there instead of repitching.

Thanks!

__________________
kenpotf is offline
 
Reply With Quote Quick reply to this message
Old 07-28-2014, 12:35 PM   #4
Pappers_
Moderator
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
Pappers_'s Avatar
Recipes 
 
Join Date: Jan 2009
Location: Chicago
Posts: 12,107
Liked 1034 Times on 723 Posts
Likes Given: 2110

Default

Using calculators to predict your FG isn't very valuable, in my opinion. There are many variables involved, specific to your process and setup, and the FG will be whatever it is, regardless of the prediction. If a batch ends up too low or too high, you can make adjustments for your next batch, but for the batch you are currently doing, you just need to let the yeast determine what your FG will be.

__________________
http://www.singingboysbrewing.com

My wife's book "Uncovering Lives: Discovering One Immigrant Generation's Secrets and Lives of Forgiveness, Grace and Healing"


"People who ask a question want a conversation as much as they want an answer." b-boy
Pappers_ is offline
pdxal Likes This 
Reply With Quote Quick reply to this message
Old 07-28-2014, 01:08 PM   #5
Demus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2011
Location: Orlando, FL
Posts: 1,227
Liked 157 Times on 128 Posts
Likes Given: 6

Default

Did you calibrate ur refract with distilled water first? It's amazing how easily they seem to drift off. I do mine before each use....


Sent from my iPhone using Home Brew

__________________
Demus is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hydrometer or refractometer? Pete_WNY Beginners Beer Brewing Forum 11 01-22-2014 10:18 PM
Hydrometer misreading jordanhollins Beginners Beer Brewing Forum 5 04-14-2012 12:19 AM
Hydrometer/Refractometer Bonestar Beginners Beer Brewing Forum 4 01-30-2012 01:56 AM
Refractometer and Hydrometer? Airplanedoc Beginners Beer Brewing Forum 7 01-26-2012 01:38 AM
reading a hydrometer and hydrometer vs. refractometer deanocamino Brew Science 12 09-15-2011 10:04 PM



Newest Threads

LATEST SPONSOR DEALS