tag:blogger.com,1999:blog-6381925904699185711.post5882627271476809441..comments2024-03-23T10:51:56.649-07:00Comments on Diversity - Petr Novotný: Počítáme: Nová korekce refraktometruPetr Novotnýhttp://www.blogger.com/profile/13877895909797882858noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-6381925904699185711.post-32363935176609489552019-11-10T08:54:42.473-08:002019-11-10T08:54:42.473-08:00Hi Evan, unfortunately the raw data is not availab...Hi Evan, unfortunately the raw data is not available. It comes from proprietary work of Czech Budějovice Budvar. I have validated the results with my data as well. Have not brewed anything that strong, though. The highest OG I tried was 1.085 and it worked just fine. By the way, this was published in Zymurgy if you prefer English version. There also little bit more in depth information in that article. Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-3993376763438873522019-11-10T06:28:36.008-08:002019-11-10T06:28:36.008-08:00This article is very interesting. I recently star...This article is very interesting. I recently started using a refractometer in my brew process and have frustrated to discover just how muddy determination of beer IG/FG can be. I have a few questions about your anaylsis here: I am curious how well your method performs for higher IG. Did you try any batches with greater IG, like 1.100? Also, is your raw data available? I am curious to learn more about how you arrived at the results you presented here, or possibly supplement them with some higher IG measurements of my own.Evanhttps://www.blogger.com/profile/07283585711957028208noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-58807966002481774932019-04-13T00:49:59.640-07:002019-04-13T00:49:59.640-07:00Agree. This can be due to my specific refractomete...Agree. This can be due to my specific refractometer, which is not the best in class, by far :). Anyway, your formula results are great - in my case always within 0-0.002 SG margin, and if I account for my specific offset, then it is +/-0.001 SG.Bartekhttp://projektcydr.plnoreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-64957926631426591572019-04-12T09:54:16.321-07:002019-04-12T09:54:16.321-07:00That's actually great result...That's actually great result...Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-35044558952513848302019-04-12T09:53:11.146-07:002019-04-12T09:53:11.146-07:00I didn't have the time carefully read that pap...I didn't have the time carefully read that paper but values can vary in the literature, that paper looks like they dealt with very high pressure which can also make a difference. Fo me, it was not important since after accounting for CO2 (either value) I'm within experimental error of my instruments. I believe you are, too. Your hydrometer is great but still bubbles and even tiny ones can affect it, moreover refractometer with 0,1 Bx precision corresponds to precision of 0,0005 SG and you used it twice during measurnment, and then there are all sort of other things can have effect on it. So, if your offset is only 0,0011 which is about 0,25 Bx then I don't really see a reason for trying to chase precison anymore since it is most likely not possible.Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-70973575370874931332019-04-11T23:45:11.854-07:002019-04-11T23:45:11.854-07:00Yes, my results are offset to formula with +0,0011...Yes, my results are offset to formula with +0,0011 SG. From what I understood, you had similar observation: formula lower by 0,001-0,002 comparing to real measurement - or did I get it wrong?<br /><br />My point is that CO2 cannot explain the whole offset. According to this paper: https://www.osti.gov/servlets/purl/790022, the density increase due to 2g/L dissolved CO2 can account only for +0,0003SG. <br /><br />This is lower than what you found in the other paper, but that one is probably discussing deep sea/salty water under high pressure - did not get a full text, only abstract.Anonymoushttps://www.blogger.com/profile/17805951124487333893noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-38248898736548424192019-04-11T18:34:27.835-07:002019-04-11T18:34:27.835-07:00I thought that you were talking about an offset of...I thought that you were talking about an offset of your result vs. my formula. When accounted for dissolved CO2 my formula worked for me, spot on (within exp error). If you have additional offset that can't be explained by CO2 then I guess it is perhaps due to differences between cider and beer wort or calibration of the refractometer or other instrument-based discrepancies.Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-75492346660186233002019-04-11T11:12:28.880-07:002019-04-11T11:12:28.880-07:00But didn't you observe exactly the same offset...But didn't you observe exactly the same offset with out experiment? You motivated this as an effect of CO2 saturation, but that cannot exaplain the whole offset, or? Bartekhttp://projektcydr.plnoreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-24169441253065292742019-04-11T08:46:03.656-07:002019-04-11T08:46:03.656-07:00Interesting. If there is only offset that probably...Interesting. If there is only offset that probably indicates that the yeast ferments both beer and cider in the same way, which is not a surprise. I think that the offset is due to the fact that cider and beer have slightly different refractive indices because of differences in sugar composition.Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-5190757300007254772019-04-11T06:37:57.821-07:002019-04-11T06:37:57.821-07:00Interesting, I have done similar work for cider. I...Interesting, I have done similar work for cider. I measured 45 samples from the same juice, at different stages of fermentation, using a high precision hydrometer (0.0002 SG) and a 0-18 Brix refractometer with a 0,1 precision scale (SG corrections for temperature and refractometer calibration accounted for).<br /><br />For initial SG 1.055 I got following formula: <br />realBrix = 1,56201 * measuredBrix - 7,64495<br /><br />Which is exactly the same as yours (!), except there is a constants and consistent offset of 0,0011 SG - your results are lower.<br /><br />Even if part of the offset is due to dissolved CO2 (I measured fully saturated), still half of the difference remains.<br /><br />I am trying to understand the reason. Perhaps the guys that did the original formulas input to your work did it in some specific way that affected the results. Or there is some round-up error in the math.. Will continue digging, but curious for your thoughts.Bartekhttp://projektcydr.plnoreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-92067726812211516382017-01-16T08:29:44.564-08:002017-01-16T08:29:44.564-08:00Díky. Ano, přesně tak rozcházejí. Některé jsou na ...Díky. Ano, přesně tak rozcházejí. Některé jsou na tom dobře, ale ti si to drží jako know-how, což nemám rád, protože si myslím, že homebrewing je právě o tom sdílení. Říci někomu dělej to takhle, nikomu nepomůže. Vysvětlit ale jak a k tomu PROČ, to je to důležité. Já nikdy nehodlám dělat žádnou komerci ohledně znalostí, znalosti se mají sdílet s ostatními, aby jsme byli všichni chytřejší! ;-)Petr Novotnýhttps://www.blogger.com/profile/13877895909797882858noreply@blogger.comtag:blogger.com,1999:blog-6381925904699185711.post-12193026575907245492017-01-16T07:00:10.612-08:002017-01-16T07:00:10.612-08:00Dobrý den,
díky mockrát za tuhle práci. Už dříve j...Dobrý den,<br />díky mockrát za tuhle práci. Už dříve jsem si všiml, že se různé korekční vztahy pro refraktometry podivně rozcházejí, pokud je použiji pro jiné podmínky, než těsně před stáčením. Tady je vysvětlení a navíc řešení.<br /><br />S pozdravem,<br />Marcel D. Anonymousnoreply@blogger.com