Spiderman2286
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Want to do a sg test. Anything I can do this in other than a test tube. First ever brew
Sg test
- Thread starter Spiderman2286
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Something like this? Wilko Plastic Trial Jar | Wilko
Or you could sterilize the hydrometer and pop it in the beer in a push..
Or you could sterilize the hydrometer and pop it in the beer in a push..
,,,,,,
Deffo the plastic trial jar, Reeves fragile hydrometers, de-gass, temp compensation charts, calculator, HMRC tables. Sanitise, dry and put those puppies carefully to bed again.
Take a sample if at all possible, rather than drop the hydrometer in (it might break,, )
Deffo the plastic trial jar, Reeves fragile hydrometers, de-gass, temp compensation charts, calculator, HMRC tables. Sanitise, dry and put those puppies carefully to bed again.
Take a sample if at all possible, rather than drop the hydrometer in (it might break,, )
Last edited:
peebee
Out of Control
This will do your head in! It will do the heads in of a lot of experienced brewers too! It has been doing my head in for a while recently. But you've probably got the equipment in your kitchen already. You need:
1 litre measuring jug.
Fairly accurate kitchen scales (weigh a kilo and a bit at 1g increments).
Marker (fine pen type, bit of tape, whatever will put a precise mark on your jug).
Your water and beer (I presume its wort to be fermented) needs to be about the same temperature. About 16 to 20°C.
Place jug on scales. Tare (zero scales) and fill with water until measuring 1000g (1 litre). Mark level of water. Clean and sanitise jug. Carefully fill with beer/wort up to mark. Weigh jug (you've hopefully still got the scales tared or reading zero with just the jug). Put the beer carefully back with the rest (hopefully you have been keeping the jug sanitised!).
Optionally divide the weight by 1000 (do it in your head) so if the beer weighed 1045g to the marker, the SG is 1.045.
There is a bit more to SG than that example suggests, but it will get your results. I do this all the time now 'cos my eyesight is dodgy, but I use reasonably precise scales (weigh 500g to 0.01g increments) and a much smaller sample (25ml) in a pycnometer bottle. To give a clue of the "bit more": If the temperature was 20°C your results were SG(20°C/20°C) or the same as most home-brew hydrometers tell you (I only added that snippet in case anyone wants to argue - they can do the explaining of SG(20°C/20°C) and save me from doing it).
1 litre measuring jug.
Fairly accurate kitchen scales (weigh a kilo and a bit at 1g increments).
Marker (fine pen type, bit of tape, whatever will put a precise mark on your jug).
Your water and beer (I presume its wort to be fermented) needs to be about the same temperature. About 16 to 20°C.
Place jug on scales. Tare (zero scales) and fill with water until measuring 1000g (1 litre). Mark level of water. Clean and sanitise jug. Carefully fill with beer/wort up to mark. Weigh jug (you've hopefully still got the scales tared or reading zero with just the jug). Put the beer carefully back with the rest (hopefully you have been keeping the jug sanitised!).
Optionally divide the weight by 1000 (do it in your head) so if the beer weighed 1045g to the marker, the SG is 1.045.
There is a bit more to SG than that example suggests, but it will get your results. I do this all the time now 'cos my eyesight is dodgy, but I use reasonably precise scales (weigh 500g to 0.01g increments) and a much smaller sample (25ml) in a pycnometer bottle. To give a clue of the "bit more": If the temperature was 20°C your results were SG(20°C/20°C) or the same as most home-brew hydrometers tell you (I only added that snippet in case anyone wants to argue - they can do the explaining of SG(20°C/20°C) and save me from doing it).
Spiderman2286
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Cant I just syphon it into a pint glass and do it in that
peebee
Out of Control
Answering me? If so:
I chose 1 litre because there's no maths to speak of and anything less will need ever more precise weighing scales. So, "pint glass" (568ml)? Probably not. You could try, with a 500ml (500 grams of water) and double the result. 500ml of 1.045 wort at 20° C will weigh 522-523g. You can't be sloppy with the measurements I'm afraid. And weigh the water, don't use the dodgy markings on any jug.
I chose 1 litre because there's no maths to speak of and anything less will need ever more precise weighing scales. So, "pint glass" (568ml)? Probably not. You could try, with a 500ml (500 grams of water) and double the result. 500ml of 1.045 wort at 20° C will weigh 522-523g. You can't be sloppy with the measurements I'm afraid. And weigh the water, don't use the dodgy markings on any jug.
peebee
Out of Control
There is a tiny error in my "computations". I'm surprised no-one picked me up on it.
There will be a prize for anyone picking it out. And the prize will be … you get to write out the mathematical proof! You will also explain how kitchen scales are accurate enough for it to make significant difference. Actually, that makes my results closer to SG(20°C/4°C), something I didn't notice: As an extra bonus prize explain that!
Clue: 1 litre of pure water @ 20°C weighs 998.2g, not 1000g, and having proved that then all the rest of the maths gets "difficult". Perhaps it is just not worth going there.
There will be a prize for anyone picking it out. And the prize will be … you get to write out the mathematical proof! You will also explain how kitchen scales are accurate enough for it to make significant difference. Actually, that makes my results closer to SG(20°C/4°C), something I didn't notice: As an extra bonus prize explain that!
Clue: 1 litre of pure water @ 20°C weighs 998.2g, not 1000g, and having proved that then all the rest of the maths gets "difficult". Perhaps it is just not worth going there.
I think we can apply that to the whole thing. I suggest the OP gets a hydrometer and a plastic trial jar or a refractometer.
peebee
Out of Control
You obviously haven't picked up any sense of urgency? I got the impression @Spiderman2286 wanted an SG reading now, not next week. But you're right, the described weighing method is not precise enough or convenient enough for everyday use. Although a couple of quid on a hydrometer doesn't buy anything slightly close to "precision" either. If I saved anyone from buying a poxy "hydrometer" I've done a good job. Refractometers are pretty good, if you can get your head around the BRIX conversion calculators (some people can't, not helped by some refractometers having useless SG scales).
peebee
Out of Control
Just as a side-line, this is NOT an answer to the OP, here's the weighing method done properly:
But there is still a bit of work with a calculator to convert that weight to SG. But the pycnometer bottle (25ml) doesn't require excellent vision to fill (no lining up fine lines and surface meniscus and stuff). The weigh scales do cost 2 or 3 times more than the cheap Chinese postage stamp sized ones that can only claim to measure 2 decimal places of a gram (they can do nothing of the sort).
And it is accurate, something you can only pretend a home-brew hydrometer is.
But there is still a bit of work with a calculator to convert that weight to SG. But the pycnometer bottle (25ml) doesn't require excellent vision to fill (no lining up fine lines and surface meniscus and stuff). The weigh scales do cost 2 or 3 times more than the cheap Chinese postage stamp sized ones that can only claim to measure 2 decimal places of a gram (they can do nothing of the sort).
And it is accurate, something you can only pretend a home-brew hydrometer is.
If he has a Wilko near him then he can pick up a hydrometer pretty quickly and it will be accurate enough for most homebrewers purposes
A home brew hydrometer is perfectly good enough for most home brewers. We don't need to measure SG very accurately.
peebee
Out of Control
We are both guilty of assuming what "Spiderman2286's" circumstances are based on our own experience:
Wilco? What's a Wilco? Blimey, there is one in my closest big town. That's 35 miles away. I'll jump in my car. Wonder if I'm allowed to do that during "lockdown" (Wales)? Ah, don't matter I had to surrender my driving licence several years ago.
I'm getting earache for thinking "Spiderman2286"doesn't have access to a local home-brew shop. But imagine the earache I'd give if anyone suggested I went to a local home-brew shop.
My post was clearly presented as a "side-line", some background info, and not an attempt at answering the OP. But what I meant was:
Search this site for "hydrometer slipped". I think you are correct thinking "a home brew hydrometer is perfectly good enough for most home brewers", but the rest of "most home-brewers" are just being fooled into thinking a hydrometer is good enough. And the blasted things break as soon as look at them.
No, a pint glass isn't tall enough for a hydrometer, I just checked with mine.
Personally I always sanitise my hydrometer and drop it in the fermenting bin. Has worked without problems for 40+ years.
No good I suppose if you're not fermenting in a bin. I always have trouble with wine in demijohns.
Drunkula
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Mine can. I've tested them with weights n stuff.
peebee
Out of Control
Try it again! The fault I found with them wasn't so much accuracy and precision, it was repeatability. Weighing 0.01 gram is apparently a piece of paper the size of a full-stop. Weighing to such ludicrously small amounts is only to keep sample sizes manageable, as illustrated by my initial posts using a 1 litre sample so you only need weigh in precisions of a gram (kitchen scales).
