Can I have you attenuation please!

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BartonMillBrewer

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Hi
Ever since I have been using my 30L microbrewery I have an issue with attenuation that I hope someone can throw light on.

I treat the water to get Ph of 5.5 and calcium around 80ppm.
My liquors are 17L for mash, 12L for sparge.
Mash temperature around 66C
I use around 5Kg of grain; at the moment Saaz and Maris Otter.
Mash time, 1 hour, boil time 1 hour.
Pitching rates typically 1 or 2 sachets at around 20C.
I use an Inkbird to retain temperature at 19C.
Gravity is read with a refractometer with a brix scale. I calibrate each time of use against water and use a hydrometer for confirmation.
Initial gravity, without additional sugar, around 1.045
Regardless of additional sugar, grain bill or yeast used my batches only ever attenuate to a gravity no lower than 1.020.

Previously I used grain in a bag in my Berco boiler type water heater and would consistently get final gravity of 1.005. This was without treating the water, suggesting the water is not the root of the issue.

Any ideas?
 

Clint

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You need to tell us what yeast you're using...
 

Hazelwood Brewery

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How are you measuring temperature?

Are you recirculating through the mash?

How long are you fermenting?

How are you determining fermentation is complete?

What are you using to measure the gravity of your finished beer?
 

foxbat

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You can't use a refractometer once fermentation has started*. Hydrometers only from that point on.

* actually you can if you take enough records and calculate an adjustment factor but really... just use the hydrometer.
 

BartonMillBrewer

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How are you measuring temperature?

Are you recirculating through the mash?

How long are you fermenting?

How are you determining fermentation is complete?

What are you using to measure the gravity of your finished beer?
Using the thermometer built into the microbrewery. Admittedly I have not checked temperature with a second thermometer.
Recirculation using the recirculating pump in the microbrewery
Ferment for 3 weeks.
Determining fermentation complete as gravity stops dropping. Gravity drops over 2 weeks to the 1.020 level and then stops
Using a refractometer and taking a second confirmation read using a hydrometer.
 

BartonMillBrewer

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You can't use a refractometer once fermentation has started*. Hydrometers only from that point on.

* actually you can if you take enough records and calculate an adjustment factor but really... just use the hydrometer.
A hydrometer measures current specific gravity of a given liquid. It can be used in any liquid at any time, assuming ambient temperature. It is convenient in brewing to determine the conversion of sugar to alcohol.
 

Hazelwood Brewery

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OK. Yes, check the thermometer against whatever you used previously. If you are mashing at a higher temp than you think then you will be producing a high proportion of unfermentable sugars resulting in a high final gravity.

Recirculation is good, it means the whole grain bed should be at the same temperature.

3 weeks is a good length of time for fermentation at those temperatures and original gravity.

You can’t use a refractometer for measuring the gravity of your fermenting/fermented beer - alcohol throws out the reading. Use your hydrometer.

I suspect your problem is mash temperature.
 

BartonMillBrewer

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OK. Yes, check the thermometer against whatever you used previously. If you are mashing at a higher temp than you think then you will be producing a high proportion of unfermentable sugars resulting in a high final gravity.

Recirculation is good, it means the whole grain bed should be at the same temperature.

3 weeks is a good length of time for fermentation at those temperatures and original gravity.

You can’t use a refractometer for measuring the gravity of your fermenting/fermented beer - alcohol throws out the reading. Use your hydrometer.

I suspect your problem is mash temperature.
I'll heat some water this evening and check against a separate thermometer. Thanks for your reply.
 
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