Re: [Biofuel] Fw: Electronic PH meter
Hi, Is phenolphtalein the same as phenol red ? Met dank en vriendelijke groet, Pieter Koole - Original Message - From: bob allen [EMAIL PROTECTED] To: Biofuel@sustainablelists.org Sent: Saturday, June 18, 2005 3:52 PM Subject: Re: [Biofuel] Fw: Electronic PH meter Howdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits? If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly. Because density is a function of temperature, how accurately does one know the temperature? How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water. If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.) Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc. I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand. Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ -- Bob Allen http://ozarker.org/bob Science is what we have learned about how to keep from fooling ourselves - Richard Feynman ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
[Biofuel] Fw: Electronic PH meter
Hello Pieter Hi, Is phenolphtalein the same as phenol red ? No. You've already got the link, below: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate It says: Phenolphthalein is often confused with phenol red, obtained at pool supply stores and used for checking water. It's not the same thing, and phenol red won't really do for titrating WVO, its pH range isn't broad enough. It ranges from pH 6.8, at which point it's yellow, through orange, to a maximum of pH 8.2, red. For accurate titration you need to be able to measure pH 8.5. Phenolphthalein is colorless up to pH 8.3, then it turns pink (magenta), and red at its maximum of pH 10.4. When it stays pink for more than 10 seconds, it's measuring pH 8.5. With good-quality oil with low FFA levels you might just get away with using phenol red for titration, but for higher FFA levels it isn't accurate enough. Use 1% phenolphthalein solution (1.0w/v%). Why don't you read the whole page, Pieter? Both pages: http://journeytoforever.org/biodiesel_make.html Make your own biodiesel http://journeytoforever.org/biodiesel_make2.html Make your own biodiesel - page 2 Keith Met dank en vriendelijke groet, Pieter Koole - Original Message - From: bob allen bob at ozarker.org To: Biofuel at sustainablelists.org Sent: Saturday, June 18, 2005 3:52 PM Subject: Re: [Biofuel] Fw: Electronic PH meter Howdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits? If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly. Because density is a function of temperature, how accurately does one know the temperature? How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water. If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.) Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc. I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand. Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] Fw: Electronic PH meter
Thanks Keith. Pieter Koole - Original Message - From: Keith Addison [EMAIL PROTECTED] To: Biofuel@sustainablelists.org Sent: Sunday, June 19, 2005 2:05 PM Subject: [Biofuel] Fw: Electronic PH meter Hello Pieter Hi, Is phenolphtalein the same as phenol red ? No. You've already got the link, below: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate It says: Phenolphthalein is often confused with phenol red, obtained at pool supply stores and used for checking water. It's not the same thing, and phenol red won't really do for titrating WVO, its pH range isn't broad enough. It ranges from pH 6.8, at which point it's yellow, through orange, to a maximum of pH 8.2, red. For accurate titration you need to be able to measure pH 8.5. Phenolphthalein is colorless up to pH 8.3, then it turns pink (magenta), and red at its maximum of pH 10.4. When it stays pink for more than 10 seconds, it's measuring pH 8.5. With good-quality oil with low FFA levels you might just get away with using phenol red for titration, but for higher FFA levels it isn't accurate enough. Use 1% phenolphthalein solution (1.0w/v%). Why don't you read the whole page, Pieter? Both pages: http://journeytoforever.org/biodiesel_make.html Make your own biodiesel http://journeytoforever.org/biodiesel_make2.html Make your own biodiesel - page 2 Keith Met dank en vriendelijke groet, Pieter Koole - Original Message - From: bob allen bob at ozarker.org To: Biofuel at sustainablelists.org Sent: Saturday, June 18, 2005 3:52 PM Subject: Re: [Biofuel] Fw: Electronic PH meter Howdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits? If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly. Because density is a function of temperature, how accurately does one know the temperature? How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water. If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.) Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc. I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand. Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel
Re: [Biofuel] Fw: Electronic PH meter
Howdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits? If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly. Because density is a function of temperature, how accurately does one know the temperature? How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water. If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.) Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc. I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand. Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ -- Bob Allen http://ozarker.org/bob Science is what we have learned about how to keep from fooling ourselves - Richard Feynman ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] Fw: Electronic PH meter
Howdy Bob Howdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits? You can measure 4ml four times as accurately, so use 4ml and divide by 4. See: Better titration http://journeytoforever.org/biodiesel_make2.html#bettertitrate Accurate measurement http://journeytoforever.org/biodiesel_make2.html#measure This is one of the reasons, among the more obvious ones, that we always recommend starting with one-litre test batches - you learn precision that way. Or as much precision as you're capable of. If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly. That will start to matter when you get to high-FFA oils titrating at say 7 or 8ml or above, very marginal at less than that IMHO. We've processed higher titration oils than 7 or 8 accurately and reliably (single-stage base) using pH meters, but phenolphthalein wasn't reliable at that level. Because density is a function of temperature, how accurately does one know the temperature? At processing temperature. How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water. Bob, how can it be a non-aqueous solution when you're adding 0.1% v/w NaOH (or KOH) solution which is 99.9% water? If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.) But it will be the same as what's encountered in the subsequent processing. Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc. We've had three different pH meters, well-calibrated and maintained, in consistent agreement and differing from phenolphthalein results, and the pH meter results were consistently borne out by the subsequent processing results, whereas phenolphthalein were off, this with high-FFA oils where you can really see the difference. The phenolphthalein was obtained from two different lab supply houses and was fresh. We use phenolphthalein for demos and at our seminars because of the pretty pink colour and it's a cheap entry, but we seldom use it otherwise. At our workshops we use pH meters. I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand. To each his own Bob. Best wishes Keith Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] Fw: Electronic PH meter
I haven't done much with biodiesel yet, but I can shed some light on pH meters vs. phenolphthalien(PHTH) from a chemist's perspective. As acids become weaker, it is important to become more careful in the selection of a chemical indicator (such as PHTH), as the change in pH is much slower than it is for a strong acid titration. PHTH is the most commonly used indicator for strong acid titrations because it has such a clear color change. Fortunately it appears to change color over the same range as the equivalence pt. for FFAs. The difficulty in either method is knowing what the equivalence point is going to be. This will vary based on the type of oil and the degree of hydrogenation. I don't suspect it will vary much, but it will vary. If your goal is a pH of 8 or 9, then usingPHTH is going to be as good as a pH meter. If you have a better idea of what the equivalence point is going to be, then a pH meter works better. And if you haven't a clue, there is a rather tedious method of determining what it should be using a pH meter. I'll probalby use this method myself at least once so I have a better understanding of the behavior, but I wouldn't necessarily recommend it for everyone, and I certainly am not going to do it for each batch. The point is there are a number of reasons why PHTH may not work as well as a pH meter in some cases yet works fine in other cases. This is something I think everyone will have to decide for themselves. Keith Addison [EMAIL PROTECTED] wrote: Howdy BobHowdy Kieth and Willem, the issue of the use of a pH meter as opposed to other methods for determination of the end point of a titration comes up from time to time. It seems that many believe one really needs a pH meter. I think not and here is why. Although a pH meter may be more accurate if all the variables were tightly controlled, they're not. How accurately can one measure the 1 ml of oil? One maybe two significant digits?You can measure 4ml four times as accurately, so use 4ml and divide by 4. See:Better titrationhttp://journeytoforever.org/biodiesel_make2.html#bettertitrateAccurate measurementhttp://journeytoforever.org/biodiesel_make2.html#measureThis is one of the reasons, among the more obvious ones, that we always recommend starting with one-litre test batches - you learn precision that way. Or as much precision as you're capable of.If different oils have different densities, (they do but small) then one should really adjust the volume of oil used in the titration accordingly.That will start to matter when you get to high-FFA oils titrating at say 7 or 8ml or above, very marginal at less than that IMHO. We've processed higher titration oils than 7 or 8 accurately and reliably (single-stage base) using pH meters, but phenolphthalein wasn't reliable at that level.Because density is a function of temperature, how accurately does one know the temperature?At processing temperature.How accurately can one prepare the titrant solution? How accurately can one measure the titrant? Finally the titration is done in a nonaqueous heterogeneous solution, hence pH isn't even strictly defined; pH being defined as minus the log of the hydrogen ion concentration in water.Bob, how can it be a non-aqueous solution when you're adding 0.1% v/w NaOH (or KOH) solution which is 99.9% water?If you heat the oil/isopropyl alcohol mix to get homogeneity, the hydrogen ion concentration changes. (It is actually worse, it is the hydrogen ion activity, but that is another matter.)But it will be the same as what's encountered in the subsequent processing.Hence use of a pH meter to me is overkill. What you get is a very precise endpoint for a titration which is really fairly inaccurate, due to the aforementioned difficulties in the volumetric measurements, temperature, etc.We've had three different pH meters, well-calibrated and maintained, in consistent agreement and differing from phenolphthalein results, and the pH meter results were consistently borne out by the subsequent processing results, whereas phenolphthalein were off, this with high-FFA oils where you can really see the difference.The phenolphthalein was obtained from two different lab supply houses and was fresh. We use phenolphthalein for demos and at our seminars because of the pretty pink colour and it's a cheap entry, but we seldom use it otherwise. At our workshops we use pH meters.I use phenolphthalein to determine the endpoint. It is quick, requires no calibration, costs a heck of a lot less than a pH meter, and provides sufficient precision for the measurement at hand.To each his own Bob.Best wishesKeithHi WillemHi all,I am slowly getting the parts together to construct a small biodiesel set-up(approx. 30 litres).When I told a friend recently avout my plans he gave me an electronic PHmeter, pen type. Accuracy is 1 decimal. He said this would replace thetitration, but could give me no more info.It won't replace titration, you use it for titration. You can use phenolphthalein, or
Re: [Biofuel] Fw: Electronic PH meter
on 6/18/05 1:08 PM, the skapegoat at [EMAIL PROTECTED] wrote: As acids become weaker, it is important to become more careful in the selection of a chemical indicator (such as PHTH), as the change in pH is much slower than it is for a strong acid titration. PHTH is the most commonly used indicator for strong acid titrations because it has such a clear color change. Fortunately it appears to change color over the same range as the equivalence pt. for FFAs. The difficulty in either method is knowing what the equivalence point is going to be. This will vary based on the type of oil and the degree of hydrogenation. I'm not sure, but I THINK what you're saying may be the same as my own observation with phenolphthalein, which is it displays a WIDE RANGE of pinkness. It doesn't just turn pink -- sometimes it turns pink and then turns colorless after awhile. Sometimes it's hard to tell if it's the same shade of pink it was a little earlier. I've always assumed the difference was small and didn't matter. -K ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
[Biofuel] Fw: Electronic PH meter
Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] Fw: Electronic PH meter
Hi Willem Hi all, I am slowly getting the parts together to construct a small biodiesel set-up (approx. 30 litres). When I told a friend recently avout my plans he gave me an electronic PH meter, pen type. Accuracy is 1 decimal. He said this would replace the titration, but could give me no more info. It won't replace titration, you use it for titration. You can use phenolphthalein, or pH test strips, or a pH meter - whichever you use, titration involves measuring the pH. See: Basic titration Better titration pH meters Phenolphthalein http://journeytoforever.org/biodiesel_make2.html#titrate pH meters are best, IMO. You need to calibrate them often (get calibration fluid from a lab supply) and you have to look after them properly. There's a Technical tips link at the url above. Best wishes Keith Can anyone tell me if this is so and how I convert the reading to the amount of lye to be used? Best regards, Willem ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
