Same pre boil gravity every time

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Cobnut
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Re: Same pre boil gravity every time

Post by Cobnut » Thu Oct 29, 2020 5:28 pm

Jocky wrote:
Thu Oct 29, 2020 4:05 pm
The Stevenson Reeve ones have all been within 0.002 of each other.
That would sufficient to carbonate an English ale without priming sugar.

AKA measurement error.

It amazes me that people believe their measurements are that precise, especially as many hydrometers only have a resolution of 0.002.

IIRC from the days when I studied science, measure AT LEAST 3 times and average the results. Or maybe if 2 of them are the same, assume they're right and the other one is an error. However, far from guaranteed!

It's a bit like when working with materials to be cut: Measure twice, cut once!

I have 2 hydrometers and a refractometer (and the dreaded Tilt hydrometer, but let's not start that over again...). Not sure I've ever known them all to agree on a gravity reading! #-o
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Re: Same pre boil gravity every time

Post by Bretty Biscuit » Fri Oct 30, 2020 10:06 am

Did you use 6kg of grain on previous brews, same water volumes?

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Re: Same pre boil gravity every time

Post by richard080561 » Sat Oct 31, 2020 11:55 am

MattGuk wrote:
Wed Oct 28, 2020 9:31 pm
Well for once my post boil reading is a bit higher, only by 4 points though.
1.048 even after a gallon boil off, I must be doing something wrong but I just can't figure it out lol.
At the beginning of the thread the problem was that the pre-boil gravity is always 1044
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Re: Same pre boil gravity every time

Post by Brewedout » Sat Oct 31, 2020 12:10 pm

When you take the preboil gravity are you adjusting the reading for temperature? Hot wort has a different density to wort at 20C. When hot the readings will be lower than when cool. Each hydrometer is calibrated to a particular temperature and any reading should be taken with a thermometer reading as well.

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Re: Same pre boil gravity every time

Post by MattGuk » Tue Nov 03, 2020 12:46 pm

richard080561 wrote:
Sat Oct 31, 2020 11:55 am
MattGuk wrote:
Wed Oct 28, 2020 9:31 pm
Well for once my post boil reading is a bit higher, only by 4 points though.
1.048 even after a gallon boil off, I must be doing something wrong but I just can't figure it out lol.
At the beginning of the thread the problem was that the pre-boil gravity is always 1044
1.044 was pre boil and post boil was 1.048

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Re: Same pre boil gravity every time

Post by MattGuk » Tue Nov 03, 2020 12:56 pm

I am waiting for the sample to cool down to 20°c and no matter what I do, the pre boil gravity is always 1.044 ISH, assuming I am have enough grain in the particular recipe to get me to at least that point.
My previous batch of cream ale came out the same pre boil as this batch, only weird thing is that this batch used more grain and should of had a pre boil of 1.050 according to GF.
I have ordered a refractometer and another hydro.
I know that wort should be mixed before a sample which it is, I know that the sample should be cooled to what the Hydro is calibrated too which it is.
Just seems that what my pre and post boil gravity's are almost the same even with a gallon boil off, albeit this last batch a 4 point difference but never that close to what is predicted.

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Re: Same pre boil gravity every time

Post by Jocky » Tue Nov 03, 2020 3:54 pm

McMullan wrote:
Thu Oct 29, 2020 8:59 am
16 grams sugar in 100ml water should give you about 1.060. If your hydrometer shows this then it's fine.
This is your first step to solving your problem. Very simple to do. 16g sugar in 100g water at the temperature the hydrometer was calibrated (usually printed on the side of the hydrometer). Mine's 20℃. Also check you’re reading it correctly. Some are read below the meniscus and some above. Eyeball it at the level of the meniscus.

If your hydrometer is fine, there’s something wrong with your expectations for mash efficiency; your brewing process, recipe formulation or something like that.
Have you checked your hydrometer as per above?
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Re: Same pre boil gravity every time

Post by guypettigrew » Tue Nov 03, 2020 5:53 pm

guypettigrew wrote:
Wed Oct 28, 2020 8:38 pm
Did you ever get round to checking your hydrometer in the sugar solution I suggested when you posted before? 16 grams sugar in 100ml water should give you about 1.060. If your hydrometer shows this then it's fine.

Guy
Hopefully you've checked your hydrometer at the 1.060 point, otherwise there's no point in buying a new one! Mind you, Buying a refractometer is a good idea!

1.060 is about the gravity you'd expect post boil for 6kg grain in a final volume of about 23 litres. With an overall brewhouse efficiency of about 75%.

Guy

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Re: Same pre boil gravity every time

Post by McMullan » Tue Nov 03, 2020 9:20 pm

Jocky wrote:
Tue Nov 03, 2020 3:54 pm
McMullan wrote:
Thu Oct 29, 2020 8:59 am
16 grams sugar in 100ml water should give you about 1.060. If your hydrometer shows this then it's fine.
This is your first step to solving your problem. Very simple to do. 16g sugar in 100g water at the temperature the hydrometer was calibrated (usually printed on the side of the hydrometer). Mine's 20℃. Also check you’re reading it correctly. Some are read below the meniscus and some above. Eyeball it at the level of the meniscus.

If your hydrometer is fine, there’s something wrong with your expectations for mash efficiency; your brewing process, recipe formulation or something like that.
Have you checked your hydrometer as per above?
Kind of, but I’d dissolve 16g of sugar in about 80g (ml) water then make up the volume to 100g (ml) in the hydrometer cylinder. Ideally, it should read about 1.061, but neither kitchen balances or home-brew hydrometers are precision instruments, so 1.060 is good enough.

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Re: Same pre boil gravity every time

Post by guypettigrew » Tue Nov 03, 2020 9:33 pm

'Scuse me, but isn't that what I've been saying all along? Ever since I suggested MattGuk check his hydrometer at 1.060 ages ago. Except for the two stage process for making up the 100ml.

Guy

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Re: Same pre boil gravity every time

Post by McMullan » Tue Nov 03, 2020 9:44 pm

guypettigrew wrote:
Tue Nov 03, 2020 9:33 pm
'Scuse me, but isn't that what I've been saying all along? Ever since I suggested MattGuk check his hydrometer at 1.060 ages ago. Except for the two stage process for making up the 100ml.

Guy
Yes, Guy. That's why I quoted you above. Are you on the home brew? =D>

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Re: Same pre boil gravity every time

Post by guypettigrew » Tue Nov 03, 2020 10:45 pm

Yup, of course. A bit solipsistic, but it looked like you'd edited my name out of all the quotes.

Oh, sad me. Back to the beer and listening to music. Thurston Moore, just in case anyone's interested.

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Re: Same pre boil gravity every time

Post by MattGuk » Sat Nov 14, 2020 5:32 pm

So, just an update, I am lazy and I have not done the 16g of sugar yet, however when brewing today I have noticed that my hydrometer does not move at pre boil gravity of 1.042 between temps of 51° and 20°c. I must try this hydrometer trick you mentioned but this is really weird how that gravity does not change over those temps

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Re: Same pre boil gravity every time

Post by clarets7 » Sat Nov 14, 2020 5:49 pm

Oops, you'll get shouted at :lol: :lol: :lol:
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Re: Same pre boil gravity every time

Post by clarets7 » Sat Nov 14, 2020 5:51 pm

:D To be honest, I'm always confused by my pre boil and post boil readings. It's annoying but the beer tastes the same in the end :D
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