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OG Discrepancy: Post Boil vs. Post Knockout

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  • NHBrewer23
    replied
    Glad to hear it! That should make sleeping at night a little easier. Cheers!

    Leave a comment:


  • jebzter
    replied
    Had a fun one come up last week. Did a pre-boil gravity check, everything was good. Post boil was a different story, checked all the possible sources of water ingress into the beer, everything was sealed up tight. Not to mention that if I added enough water to get the gravity as low as it was, my tank would have overflowed. The lesson from this is always to check your test equipment against a standard, got my much more expensive hydrometer out that only serves as a back up and checked the other one against it, sure enough it was out of calibration. A crack formed and allowed liquid in, throwing off the balance of the hydrometer between the start of the boil and the end.

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  • beerbeer95648
    replied
    Originally posted by Jer View Post
    Trust the readings taken from the same calibrated hydrometer that are all taken at the same temp (+/- a couple degrees). Using different instruments, or different temps, is apples and oranges.

    -J.
    Agreed, hydrometers are way less fickle. Trust the hydrometer.

    Leave a comment:


  • Jer
    replied
    Originally posted by threeviews View Post
    Thank you to all who have contributed. With all the discussion posted until now, which reading do I ultimately trust?

    1 - The hydrometer (i.e. post H.E.) - This is also negating the stratification I noticed at the fermenter's sightglass (very, very light at the top with the color increasing greatly approaching the cone). The sample port of our fermenter was positioned at the very top (probably less than a bbl) of the wort level...thinking back, the wort of this batch into the fermenter was ~64F while the hydrometer was rated for 68F. However, that still wouldn't correlate to the discrepancy between 1.078 (post H.E.) and 1.088 (flameout/whirlpool)

    2 - The refractometer (i.e. pre knockout) - The readings I reported up until post knockout were all copacetic (and the numbers of our next batch all matched...both pre H.E. and post H.E.)

    3 - Some educated guess between the pre and post H.E. readings...perhaps the wort was somewhere between to the two readings, say 1.082-1.084?

    NOTE: Moving forward, I will grab a post-boil, hot side sample for use with a hydrometer...but perhaps someone else has some more feedback.

    Thanks again,
    Brent
    Wet Ticket Brewing
    Trust the readings taken from the same calibrated hydrometer that are all taken at the same temp (+/- a couple degrees). Using different instruments, or different temps, is apples and oranges.

    -J.

    Leave a comment:


  • Jer
    replied
    Originally posted by Bainbridge View Post
    Neat! And here I am, just using ice from the ice maker like a sucker.
    I tried ice too....the thief is worth the 150$ cost. No mess, you can time the chilling and get a fairly consistent temp, and it's yet another piece of unnecessary but beautiful stainless steel!!!!

    Leave a comment:


  • threeviews
    replied
    Thank you to all who have contributed. With all the discussion posted until now, which reading do I ultimately trust?

    1 - The hydrometer (i.e. post H.E.) - This is also negating the stratification I noticed at the fermenter's sightglass (very, very light at the top with the color increasing greatly approaching the cone). The sample port of our fermenter was positioned at the very top (probably less than a bbl) of the wort level...thinking back, the wort of this batch into the fermenter was ~64F while the hydrometer was rated for 68F. However, that still wouldn't correlate to the discrepancy between 1.078 (post H.E.) and 1.088 (flameout/whirlpool)

    2 - The refractometer (i.e. pre knockout) - The readings I reported up until post knockout were all copacetic (and the numbers of our next batch all matched...both pre H.E. and post H.E.)

    3 - Some educated guess between the pre and post H.E. readings...perhaps the wort was somewhere between to the two readings, say 1.082-1.084?

    NOTE: Moving forward, I will grab a post-boil, hot side sample for use with a hydrometer...but perhaps someone else has some more feedback.

    Thanks again,
    Brent
    Wet Ticket Brewing

    Leave a comment:


  • Bainbridge
    replied
    Originally posted by Jer View Post
    If your running a system that big, why not get a thief wort chiller from Stout tanks?? I got one and I really like it. Pull a sample, champ it in, start the chill and about 70 seconds later you have a sound hydrometer reading at the right temp.

    -J.
    Neat! And here I am, just using ice from the ice maker like a sucker.

    Leave a comment:


  • barleyfreak
    replied
    Originally posted by Yellowbeard View Post
    Cynmar hydrometers have always been good for me. Try their "Plato" hydrometers which are sold in three ranges: 0-8.5, 7.5-16, and 15.5-24.

    Spreading the range between three hydrometers (which are also physically larger than standard homebrewing hydrometers) spreads out the scale so the reading precision is much greater. Accuracy also seems to be quite good for a reasonable price even if you need to buy all three.

    BSG also sells three very similar (possibly identical) hydrometers which they list as "brix saccharometers"
    +1 for the Cynmar hydrometers. I'll also throw a shout out to this digital refractometer. Yes, it is pricey, but I have also found it to quite accurate when measured against the Cynmar ones. I use it mostly to monitor runoff and hit my pre-boil gravity. It is way more accurate then any handheld refractometer I have ever used and is specifically in plato, rather than brix.

    Leave a comment:


  • jebzter
    replied
    Refractometers are effected by suspended solids, so if there is anything floating in your beer, even tiny starch particles, it will be incorrect.

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  • Jer
    replied
    Interesting, thank you. I have been frustrated with the scales on the homebrew ones, I guess the whole "there has to be a better way" just hadn't hit me yet!!!

    -J.

    Leave a comment:


  • RipRap
    replied
    Originally posted by Jer View Post
    Where does one get a non-useless hydrometer?? I'm not being a dick, I'm asking....
    Foxx Equipment has some nice ones with built in temperature correction thermometer that I really like. About $60 ish for the set of three if I remember correctly.

    Leave a comment:


  • Yellowbeard
    replied
    Non-Useless Hydrometer

    Cynmar hydrometers have always been good for me. Try their "Plato" hydrometers which are sold in three ranges: 0-8.5, 7.5-16, and 15.5-24.

    Spreading the range between three hydrometers (which are also physically larger than standard homebrewing hydrometers) spreads out the scale so the reading precision is much greater. Accuracy also seems to be quite good for a reasonable price even if you need to buy all three.

    BSG also sells three very similar (possibly identical) hydrometers which they list as "brix saccharometers"

    Leave a comment:


  • Jer
    replied
    Where does one get a non-useless hydrometer?? I'm not being a dick, I'm asking....

    Leave a comment:


  • NHBrewer23
    replied
    Since the fear of a leaking heat-exchanger has already been raised, you might want to put this fear to bed through testing. Disconnect all wort lines from the wort side of the heat-x. Run water through your cooling side with the wort inlet and outlet exposed. Initially when you turn on the water, you may see residual water get pushed out of the wort side but this is just the change in pressure on the plates squeezing out the remaining water trapped in the heat-x. Keep running the cooling water for 10 minutes or so and see if you have a constant stream of water coming out of the wort inlet and/or outlet. If you do, it would tell me you have a seal issue. If you don't see any water flow aside from the initial water when you started the flow of cooling water, your seals are fine and it should rule out the heat-x as the source of dilution.

    I hate refractometers... They are a great tool for quick ballpark values but they are not consistent. You can take three samples and have three different results. The next time you brew, I would suggest collecting a large enough sample of your pre-boil, pre-sugar, and post-boil, to be able to measure these samples with a hydrometer once the samples are cooled. Keep the samples covered as they there will be some evaporation while cooling. This will concentrate the sample. Use the refractometer as you have been and see if there are any discrepancies before any additional processes are added to the mix.

    Are you using calibrated hydrometers that have been certified? Homebrew hydrometers are pretty much useless. Do you whirlpool when adding sugar or just toss it in the boil? You may be seeing stratification if the boil isn't vigorous. You may want to whirlpool the kettle when making the sugar addition. Same goes for the post-boil sample. I would grab this sample during your whirlpool as to avoid any chance of stratification.

    Cheers,

    James

    Leave a comment:


  • Junkyard
    replied
    You were measuring the wort consistently up until knockout with a refractometer. Then switched to hydrometer after KO and found a huge difference, it seems to me one of those two instruments is out of calibration. Try measuring your post sugar flameout reading with hydrometer too.

    Leave a comment:

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