Refractometer Problem?

[redbeard]

In a recent ag brew, i found the start of 1st sparge compared to the end to be very different, let alone the 2nd sparge start & end ... perhaps thats the point - the average ?

 

[Simon W]

...then another with 10g of sugar in 100ml of water and it...

That didn't look right so I've been hunting and I think it's supposed to be 10g sugar + 90g water(90ml)
Everything I can find about the Brix scale says its this way, some state it as 10g per 100g solution(water+sugar), others a percentage, eg. 1g = 1% by weight of sugar, therefore 100deg Brix = 100% = pure sugar, 50deg = 50% = 50g sugar 50ml water.
10g in 100g water would be (10g/(10g+100g))*100 = 9.09 percent by weight of sugar or 9.09Brix

Can anyone confirm this?

 

[sah]

Is it possible that after sitting for a while, heavier sugars have fallen to the bottom, so the upper levels of the wort are slightly thinner? Maybe a stir of the wort will bring he reading back up? Just a thought.

Hi Simon,

I took the pre boil reading after stirring, however this reading is giving me the higher result so the theory doesn't hold.

The post boil sample was collected very soon after flame out. There is still a lot of turbulence at this time.

The sample for the wort cube may well not be uniform.

Thanks for highlighting this.

regards
Scott

 

[sah]

Probably a silly question, but what volume are you using for your post-boil efficiency? In kettle or into fermenter? :unsure:

Has it started fermenting?

Stuster,

You know there's no such thing as a silly question. Here's the story. I've setup my equipment in Beersmith so that it knows the final volume is 46L of that 14L is added after the boil.

In Beersmith's efficiency calculator it has a section for efficiency into boiler. That bit is easy. It also has a section for "Brewhouse efficiency based on target volume". Here you enter the actual OG, that is, after dilution or into the fermenter.

No it hasn't started fermenting after 12 hours. This is very unusual for US-56. I aerated. It's at 1.047. I've upped the temperature a fraction. I'm also having problems getting some coopers pale yeast to finish off at the moment.

Thanks for all the help.

Scott

 

[sah]

Did you calibrate your refractometer? ie, check that it reads 0 with tap (or ideally distilled) water? I gave mine a test of tap water then another with 10g of sugar in 100ml of water and it read bang on 10, so I know mine is at least as accurate as my scales. (EDIT: oops, just read PoL asked Duff this in post #5)

It's bang on 0 for tap water.

Cheers PM.

regards
Scott

 

[albrews]

It's bang on 0 for tap water.

Cheers PM.

regards
Scott

hi, yes, your brixmeter is giving reverse indication as to what is expected, in that cooled wort is denser and should give higher brix (sg) compared with hot wort. could you have had the samples mixed up?
did you use the same light source for the measurements? ie sunlight , or fluro.

cheers al

 

[sah]

hi, yes, your brixmeter is giving reverse indication as to what is expected, in that cooled wort is denser and should give higher brix (sg) compared with hot wort. could you have had the samples mixed up?
did you use the same light source for the measurements? ie sunlight , or fluro.

cheers al

Gday Al,

No chance of mixing up the samples. They were taken with a dropper (pipette). Same light source.

regards
Scott

 

[sah]

No it hasn't started fermenting after 12 hours. This is very unusual for US-56. I aerated. It's at 1.047. I've upped the temperature a fraction. I'm also having problems getting some coopers pale yeast to finish off at the moment.

I've just had a closer look at this. It looks like the US56 went through its growth stage ok. There was a good yeast cake. So I gave it a stir and gave them a stern talking to about slacking off on the job. Oh yeah, I also upped the temperature.

I'm counting on these brews to finish out before chrissy :excl:

Good day.

Scott

 

[Asher]

Scott

How did you cool your first sample?
I've heard (from somebody sensible ) that whilst dropping directly onto the cool lense some steam is given off. thus giving a slightly higher than 'true' reading.... Not sure it would add up to 4 gravity points though.

Asher for now

 

[PostModern]

That didn't look right so I've been hunting and I think it's supposed to be 10g sugar + 90g water(90ml)
Everything I can find about the Brix scale says its this way, some state it as 10g per 100g solution(water+sugar), others a percentage, eg. 1g = 1% by weight of sugar, therefore 100deg Brix = 100% = pure sugar, 50deg = 50% = 50g sugar 50ml water.
10g in 100g water would be (10g/(10g+100g))*100 = 9.09 percent by weight of sugar or 9.09Brix

Can anyone confirm this?

Hell, then my refractometer must be out. (But then again, my scales only have 2g accuracy, so I could have fluked it).

EDIT: Wikipedia has this to say:

A 25 Bx solution has 25 grams of sucrose sugar per 100 grams of liquid. Or, to put it another way, there are 25 grams of sucrose sugar and 75 grams of water in the 100 grams of solution.

 

[sah]

How did you cool your first sample?
I've heard (from somebody sensible ) that whilst dropping directly onto the cool lense some steam is given off. thus giving a slightly higher than 'true' reading.... Not sure it would add up to 4 gravity points though.

I collected with a dropper. Put some directly on the refractometer lense, took a reading. Let it cool on the lense took a reading. Cleaned the lense and put another couple of drops on from the dropper, now cooled. All three get the same result.

regards
Scott

 

[tangent]

i've found that stratification happens quicker than i expected and my readings were all over the place, depending if i took a reading from the top or the bottom of the wort. The only way i found to stop it was to take one during full boil so heaps of motion or just after transfer to the fermenter.

 

[Screwtop]

Hell, then my refractometer must be out. (But then again, my scales only have 2g accuracy, so I could have fluked it).

EDIT: Wikipedia has this to say:

But 10g of sugar aint 10g of sucrose????

 

[sah]

I've just had a closer look at this. It looks like the US56 went through its growth stage ok. There was a good yeast cake. So I gave it a stir and gave them a stern talking to about slacking off on the job. Oh yeah, I also upped the temperature.

I'm counting on these brews to finish out before chrissy :excl:

It just goes to show. Sometimes a stern talking to is all they need. The US56 brew has a good thick krausen now and the other one with the Coopers pale yeast has dropped from 7% to 6% brix today. You beauty! That's the first time since I've been checking that I've had a fermentation stall. A degree or two at the lower end can really make a difference.

regards
Scott

 

[albrews]

It just goes to show. Sometimes a stern talking to is all they need. The US56 brew has a good thick krausen now and the other one with the Coopers pale yeast has dropped from 7% to 6% brix today. You beauty! That's the first time since I've been checking that I've had a fermentation stall. A degree or two at the lower end can really make a difference.

regards
Scott
[/quote


hi scott,
i have done a successful fermentation of SPARKLING BLONDE wort at ambient temp in wollongong using coopers standard can yeast . fermentation is quick, i started sunday lunch time with a yeast starter and it is all over at around 8pm tuesday. tastes great at present as a fresh beer.

cheers alan