Finn Berger
Moderator
Hver gang jeg tror jeg har skjønt det, kommer jeg over noe som slår beina vekk under meg. I dag var det det nedenstående ( fra BYO).
"Take your wort sample in a clean glass. If the sample is from the mash, cool it down to room temperature, even if your pH meter has automatic temperature control. Taking readings of hot samples will decrease the life of the electrode. Rinse the electrode with distilled water then dry the electrode with a tissue. Don't let the tissue touch the electrode, just bring it close enough to wick the liquid away.
Place the electrode in the sample and give the sample a quick swirl. Make sure there are no bubbles attached to the electrode. Turn on the power to the electrode. The power to the electrode should never be on unless the electrode is submerged.
With the power on the electrode, the meter will take the reading. Note it in your lab notebook, then turn the power to the electrode off before pulling it out of solution. Rinse the electrode with distilled water again, dry and return to the storage solution.
Since pH changes with temperature, you need to compensate for this change. At room temperature, the pH of the cooled sample will be around 0.35 units higher than the pH at mash temperature. Thus, if you get a reading of pH 5.60 for your cooled sample, your corrected reading would be pH 5.25. (You need to do this even if your meter has temperature correction.)" http://byo.com/malt/item/1494-the-principles-of-ph
For det første: Må man virkelig gå fram så omstendelig som det beskrives her, med skylling med destillert vann osv.?
For det andre, og det er det viktigste: Hva betyr det siste? Betyr det at den lykken jeg føler når jeg måler en prøve fra mesken, nedkjølt til romtemperatur, til 5,2, er helt feil? Betyr det at ph i mesken da faktisk er 0,35 for lav, og at jeg må skynde meg å hive oppi natron for å få ph'en opp?
Jeg trodde at det tallet jeg leser i displayet når jeg måler en prøve ved romtemperatur, er det "riktige", dvs. at når det sies at den ideelle ph i mesken er 5,3, så er det 5,3 målt ved romtemperatur. Har jeg trodd feil
???
"Take your wort sample in a clean glass. If the sample is from the mash, cool it down to room temperature, even if your pH meter has automatic temperature control. Taking readings of hot samples will decrease the life of the electrode. Rinse the electrode with distilled water then dry the electrode with a tissue. Don't let the tissue touch the electrode, just bring it close enough to wick the liquid away.
Place the electrode in the sample and give the sample a quick swirl. Make sure there are no bubbles attached to the electrode. Turn on the power to the electrode. The power to the electrode should never be on unless the electrode is submerged.
With the power on the electrode, the meter will take the reading. Note it in your lab notebook, then turn the power to the electrode off before pulling it out of solution. Rinse the electrode with distilled water again, dry and return to the storage solution.
Since pH changes with temperature, you need to compensate for this change. At room temperature, the pH of the cooled sample will be around 0.35 units higher than the pH at mash temperature. Thus, if you get a reading of pH 5.60 for your cooled sample, your corrected reading would be pH 5.25. (You need to do this even if your meter has temperature correction.)" http://byo.com/malt/item/1494-the-principles-of-ph
For det første: Må man virkelig gå fram så omstendelig som det beskrives her, med skylling med destillert vann osv.?
For det andre, og det er det viktigste: Hva betyr det siste? Betyr det at den lykken jeg føler når jeg måler en prøve fra mesken, nedkjølt til romtemperatur, til 5,2, er helt feil? Betyr det at ph i mesken da faktisk er 0,35 for lav, og at jeg må skynde meg å hive oppi natron for å få ph'en opp?
Jeg trodde at det tallet jeg leser i displayet når jeg måler en prøve ved romtemperatur, er det "riktige", dvs. at når det sies at den ideelle ph i mesken er 5,3, så er det 5,3 målt ved romtemperatur. Har jeg trodd feil