Malfunctioning Plastic Coopers Hydrometer

I'm just getting started brewing so I went with one of those Coopers kits as it looked like a easy way to start. I'm doing the Lager that came in the box. So my issue is the plastic hydrometer. I took the inital SG reading after getting things going and it read 1035 (at 24C). I'm aware that bubbles can cause issues with the reading so I spun it etc. to get ride of bubbles. I set it aside to do some other things and about 15 minutes later it was reading less at around 1032. I thought this was odd so at left it another 30 minutes and it went down further to 1029. Although I thought this was odd I thought it was possible some "stuff" was coming out of solution. So I went on with the process and tonight after a week I decided to take the hydrometer reading. I got my sample and the reading was 995. So I decided this thing was going to need some calibrating and threw it in some 20C water. Well that didn't work as it sunk to almost the top of the hydrometer. I think it's reading 975 (if I scale back to the top) in 20C water. So any thoughts out there on what's going on. It doesn't appear to be taking on beer/water. I read somewhere the graduated cylinder can affected this but it doesn't seem to tight around it. The intial reading was resonable but from then on things were going down hill. Thanks for any help.

Can't really help you with your issue but a hydrometer is your best friend just like a good quality thermometer so invest in good quality reliable measuring devices if you plan on sticking with the hobby, it is money well spent!

Sounds like a un calibrated hydrometer to me. Water should read 1.000 based upon your posts you should be around 1.020 and og should have been 1.060 giving you about a 5.2% brew I my calculations are the OK. BUT based upon your post I would not trust that hydrometer and buy a proper quality glass one.

As far as the dropping reading in minutes I would take a guess if you used top off water it wasn't mixed thoroughly and the heavier solution was just separating and going to the bottom causing the reading to change

The hydrometer that came in my Cooper's kit was bad too. I contacted them and they sent me a replacement hydrometer but it too was bad. I ended up just buying a glass hydrometer from my LHBS. I suggest you do the same.

Great fermenter but sorry to say the hydrometer is a POS. Throw it out and get one from your LHBS or online.

OMO

bosco

the coopers plastic hydrometer is as useful as roller skates for goldfish.

I had a similar thing happen to my glass thermometer. Sunk like a rock. It turned out to have a small crack in it that let a tiny bit of water in. Doesn't take much.

As for the foamy mess on the top of the liquid interfering with a good reading, I start by filling the graduated cylinder nearly to the top and then put the hygrometer in. It will overflow and purge all those bubbles. Good idea to put your cylinder in the sink.

I love the fermenter.. however, I found out, after the fact, that the glass hydrometers they have/had had problems. Mine did too.. was reading off about 6 points in 60* water. I contacted them and they sent me a new plastic one that was right on. Since then, I have found others.. so, I have spares.. all reading @ 0-1 in water.

Write them.. I'll bet they send another for free.. I think the plastic is a pretty good idea for the hot wort.. not sure about the chilled wort unless you are scrupulous about keeping it sell soaked in sanitizer.. plastic being a bit more porous than glass.

Wow, great replies and really fast. Thanks for the respones. This forum/website is great.

Interesting to hear others had bad plastic hydrometers and it wasn't just mine. I guess i really don't even know what my initial reading was since it was probably bad from the start. Fortunatly the one and only brew store where I can get supplies (after a long trip) were really cool and gave me 1/2 off a glass one. I got the glass one today and it gave a good reading so I'm back on track.

Oslobrew said:

I guess i really don't even know what my initial reading was since it was probably bad from the start.

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Actually, since it is an extract brew you should be able to figure out the gravity based on what your total volume was. LME is about 37ppg (point per gallon) and the Cooper's brew enhancer is about the same as DME (I think) which is about 45-46ppg. So if you had a final volume of 6 gallons you should have had an OG around 1.040. If you had a final volume of 5 gallons you would have had an OG around 1.046-1.047.

http://www.brewersfriend.com/extract-ogfg/

Get a refractometer. I broke so many glass hydrometers over the years I could have bought several refractometers by now. so much easier to use, less wasted product for a sample.

sladek said:

Get a refractometer. I broke so many glass hydrometers over the years I could have bought several refractometers by now. so much easier to use, less wasted product for a sample.

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A refractometer is a nice instrument and it really only takes a couple of drops for a reading but you need to learn when and how to use it. If you plan on using it during or after fermentation you need to have a correction table or calculation to account for the difference in refraction of the alcohol in the solution. Your refractometer might read 1.030 when your beer is already at 1.013 and you'll be wondering how your ferment got stuck when it really didn't.:rockin: