How do you adjust Hydro reading for Temp?

Hi guys, I did my first boiling extract brew yesterday(Used all prehopped kits before that) and things did not go too smoothly, as a result of my flapping near then end (could not seem to cool the wort) the only time I took a hydrometer reading was when the wort was at 100F.

At this time it read 1.032, causing me more worry as I thought that seemed a bit low, however I have found from another post that most hydro's are calibrated to 60F. So the question is can I adjust that reading to get the correct O.G. value?

Thanks for any help.

if your hydro is calibrated at 60F your reading of 1.032 at 100 corrects to 1.038

I used BeerSmith to get that value. There is a chart here: http://www.ebrew.com/primarynews/ct_hydrometer_temp_correction.htm which would give 1.037 but I'll take the BeerSmith number.

Hope that helps.

Thanks for that, I guess my next question has to be, does 1.037-8 seem ok for the O.G. off a German style Pilsner?

I had expected the OG to be around 1.040 or higher, but I have no real experience in this so that was just a guess.

Being off by 2 points isn't that much. What was the extract/grain bill?

It was 3kg pale malt and I cant remember how much grain, I steeped, it was a kit I got from a shop. I would guess it was about 100g grain but am not sure.

This is the BJCP style guide for German pilsner.

German Pilsner (Pils)
Pilsner


Type: Lager
Category Number: 2A
Original Gravity: 1.044-1.050 SG
Color: 2.0-5.0 SRM
Final Gravity: 1.008-1.013 SG Bitterness: 25.0-45.0 IBU
Carbonation: 2.4-2.8 vols Alcohol by Volume: 4.4-5.2 %
Description: Drier and crisper than Bohemian Pilsner with a bitterness that tends to linger dur to high-sulfate water. Lighter in body and color with high carbonation.
Profile: Medium body. Dry, clean, crisp flavor with high hop bitterness. Low malt aroma and flavor. Low to medium body. Noble hops bouquet. Straw to light gold color. Clear with white head.
Ingredients: Water with moderate sulfates enhances hop falvor. German noble hops. Pilsner malt and German lager yeast.
Examples: Bitburger, Warsteiner, Koenig Pilsener, Jever Pils, Spaten Pils, Brooklyn Pilsner


BeerSmith gives a basic gravity of 1.047 in a 5 gallon batch BUT about 1.039 in a 5 imperial gallon batch. This is likely the source of the conflict. At this point. I'd strongly recommend "RDWHAHB" You may have a bit more of an ordinary bitter style with german hopping. Might be very tasty.

I don't have the book in front of me atm, but I recall the Joy of Homebrewing book said something like you add .005 for every 5 degrees past 60. I guess that could be more exact to add .01 for every degree. Of course this is just what I think I remember. You may want to disregard my whole post.

Cheers.

Never mind, just noticed that my post makes no sense.

Here's a good question. I bought my hydrometer at a petshop because I don't have any LBS as close. I used to have a reef tank so I know the typical water temp is in the low 80 degree F area. Since the packaging doesn't mention it, would you assume it was calibrated for the most accurate reading in that 80-90 temp range? I've been correcting with the assumption it was calibrated at 59, but now I'm second guessing.

3 kg (6.6lbs) of LME should yield an OG closer to 1.047, and that is not taking into consideration the small increase in OG that the steeped specialty grains will add.

John

Try taking a reading in water at 68f. Is it at 1.000? Then try it at 60f and take the reading. This should tell you if your hydro is calibrated to what temperture. The reading of 1.000 at a temp of ? will be the one temp that your hydro is calibrated to.

Then you can look up the difference 100f will give to your readings.

Bobby_M said:

Here's a good question. I bought my hydrometer at a petshop because I don't have any LBS as close. I used to have a reef tank so I know the typical water temp is in the low 80 degree F area. Since the packaging doesn't mention it, would you assume it was calibrated for the most accurate reading in that 80-90 temp range? I've been correcting with the assumption it was calibrated at 59, but now I'm second guessing.

Click to expand...

I believe that fishtank hydros are calibrated to 68 degrees. I'm not positive but I'm pretty sure. This is what I've been using with my fish tank hydro. I guess I could check the calibration with RO water. I'll try to remember to do this and post the results when I get home from Turkey day vacation.