Why is my FG so high???

[MarvinSutton]

Hi all - I have read until my eyes bleed - and private messaged folks to figure this out - need some experience here.

All of my ferments stop before completion. Here are the examples -

1. I've used both whiskey yeast and turbo yeast - both have nutrients - and i've added supplemental nutrients - so should not be the yeast
2. I have done both sugar shine and all grain - PH controlled with gypsum - my SG usually is 1.09 for sugar and 1.06 for all grain. - should not be the mash
3. I ferment at 70F which is in the range of both types of yeast. climate controlled, not much change. - so should not be my fermentation temp
4. In each case - my yeast take off for 3-4 days then peter out and presumably go dormant. I cannot resurrect with either more yeast, more sugar, or raising PH with calcium carbonate. The PH of my ferment is 3.5 - 4 when it goes dormant - yeast should be OK with that PH. - so it should not be the ferment PH
5. I have calibrated my refractometer and it is spot on with water at 68F. - so should not be measuring instrument

What else can I look at? It happens every single time regardless of mash bill, yeast, etc.

Help me experienced ones!

[yakattack]

Well for starters what is your fg measuring at? And are you checking it with a hydrometer as well? As the alcohol from the mash will squew the readings. There is a conversion formula that you can use but a simple hydrometer will be faster.

Have you tasted the finished mash? Is it sweet at all?

Here's a simple test. Take a mason jar of your finished mash, and add a bit of sugar to it. If it restarts then you know the yeast have processed all.of the available ( to them) sugars.

Some sugars are not readily fermentable and need to be broken down further in order for yeast to be able to strip the oxygen from them.

[der wo]

How high is the FG?

Can you please describe the mashing process? The amounts of what grain and water, the temperatures of the mash when adding the grains. Are the grains milled, how fine milled? How much malted barley added at what temp? Milled? How much sugar?

5. I have calibrated my refractometer and it is spot on with water at 68F. - so should not be measuring instrument

Oh oh. Here is the mistake perhaps. Refractometers are not suitable for taking FG measurements. They always measure FGs too high. There are calculators, but generally a FG is measured better with a hydrometer.
How does the fermented wash taste like? Sour or still sweet?

[der wo]

https://www.petedrinks.com/abv-calculat ... ydrometer/" onclick="window.open(this.href);return false;" rel="nofollow
This calc says a SG 1.070 and a FG 1.020 measured with a refractometer equals 1.070 and 1.003. Congratulations to the successful AG mashing! Did your stripping results verify this? Did you get around 9% alcohol?

[bluefish_dist]

Try splitting the nutrients 2/3 and 1/3. Add 2/3 at pitch and 1/3 24 hrs later. Also adjust the ph at pitch to 5.1 to 5.4. If those two things don't help, then add more nutrients.

[NZChris]

Use a hydrometer.

How do you know that the ferment has truly gone dead. If you are watching an airlock, it only takes a tiny leak to fool a newbie.

[MarvinSutton]

Der Wo - you nailed it - I am getting stopped at FG 1.02 on my refractometer reading. On a 5 gallon wash I came out with a quart of 150 proof and a quart of 120 proof. I likely left some abandoned in the tails - so very likely I had 7-9%

I just input my Brix equivalent into a Brix to ABV calculator and calculated 7.86% - which means nothing was wrong and i just don't know how to use a refractometer!!!
https://www.brewersfriend.com/refractometer-calculator/" onclick="window.open(this.href);return false;" rel="nofollow

I must have missed the memo on the wort collection factor! Here is something found on homebrew "The refractometer is designed to read samples of sugar water and fruit juice, not wort. You can determine your refractometer's wort correction factor. To do so, you need to take concurrent hydrometer readings. The wort correction factor is usually around 4%"

[MarvinSutton]

NZChris - I think you are spot on the solutions. thanks all!

[Jimbo]

This is my favorite calc. It's the Bopeel master slicer dicer for refrac measurements.

http://onebeer.net/refractometer.shtml" onclick="window.open(this.href);return false;" rel="nofollow

[Truckinbutch]

Cook your mash or boil your sugar wash . When it's cool enough , if it tastes sweet , pitch yeast and some crushed oyster shell . When it tastes bitter ; rack , filter , and run .
You are a hobby distiller trying to find your way to a good drop . Do that and proceed from there to greater things .
You can run yourself away from the hobby by overthinking it .