Killshakes
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- May 18, 2017
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I picked up a Milwaukee MA884 digital refractometer a few months back, which I use for taking pre-boil wort gravity and OG readings. I still use my glass hydrometer for FG readings. The MA884 has worked well so far, but I've noticed one quirk that has me wondering if I'm using optimally: If I let a test sample sit on the reader / lens for a while--maybe ten minutes--and then retest it, the gravity reading is always higher.
Case in point: Last night I brewed a Saison. I took a small sample of the boiled wort that had been chilled to approximately 70 degrees and allowed it to sit for a minute or two before testing it on the recently-calibrated MA884. Result: 12.9 Brix, or 1.053 SG. I then left the sample sitting on the MA884 for about ten minutes and retested it by hitting the "read" button again. Result: 14.8 Brix, or 1.063 SG.
That's a pretty big difference in OG, and by extension, efficiency--something like 65% to 77%, or a difference of about 12%. It has me wondering: Which is the more reliable reading? 1.063 is much closer to my expected OG (1.060), and that sample did have more of a chance to come to the same temperature as the MA884 / the room. However, the MA884 supposedly provides temperature compensated readings, and I wonder if some chemical change might have occurred in the wort during its ~10 minute rest on the lens that could influence the results of the machine.
What do you think? Do any of you have experience with digital refractometers, and if so, have you encountered something like this yourself? Let me know.
Case in point: Last night I brewed a Saison. I took a small sample of the boiled wort that had been chilled to approximately 70 degrees and allowed it to sit for a minute or two before testing it on the recently-calibrated MA884. Result: 12.9 Brix, or 1.053 SG. I then left the sample sitting on the MA884 for about ten minutes and retested it by hitting the "read" button again. Result: 14.8 Brix, or 1.063 SG.
That's a pretty big difference in OG, and by extension, efficiency--something like 65% to 77%, or a difference of about 12%. It has me wondering: Which is the more reliable reading? 1.063 is much closer to my expected OG (1.060), and that sample did have more of a chance to come to the same temperature as the MA884 / the room. However, the MA884 supposedly provides temperature compensated readings, and I wonder if some chemical change might have occurred in the wort during its ~10 minute rest on the lens that could influence the results of the machine.
What do you think? Do any of you have experience with digital refractometers, and if so, have you encountered something like this yourself? Let me know.