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#1 matt6150

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Posted 31 March 2015 - 05:28 PM

What is the difference between %ADF and %RDF? And which one do most people/yeast company's refer to?



#2 HVB

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Posted 31 March 2015 - 05:47 PM

ADF is the common one I believe. I think Brewing Classic Style explains them but I can't find my copy.

#3 3rd party JKor

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Posted 31 March 2015 - 06:02 PM

Apparent is what most people reference.  It's generally what homebrewers refer to as 'attenuation'.  It assumes that fermenting to 1.000 is 100% fermentation, i.e. doesn't account for alcohol produced.

 

For example, we say a beer that goes from 1.100 to 1.020 attenuated 80% (or 80% ADF), we would also say a beer that went from 1.030 to 1.006 attenuated 80%, but the percentage of sugars actually converted is different in both cases due to the effect of alcohol on the specific gravity.  The actual % of dissolved sugars fermented would be RDF.

 

At least, that's how I recall it.  :)



#4 matt6150

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Posted 31 March 2015 - 07:30 PM

Apparent is what most people reference.  It's generally what homebrewers refer to as 'attenuation'.  It assumes that fermenting to 1.000 is 100% fermentation, i.e. doesn't account for alcohol produced.

 

For example, we say a beer that goes from 1.100 to 1.020 attenuated 80% (or 80% ADF), we would also say a beer that went from 1.030 to 1.006 attenuated 80%, but the percentage of sugars actually converted is different in both cases due to the effect of alcohol on the specific gravity.  The actual % of dissolved sugars fermented would be RDF.

 

At least, that's how I recall it.  :)

Good explanation, thanks!



#5 3rd party JKor

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Posted 31 March 2015 - 09:10 PM

I should've said a FG of 1.000 is 100% attenuation, not 100% fermentation.



#6 Brauer

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Posted 01 April 2015 - 04:40 PM

In a round-about way, it's also why a higher OG beer is sweeter than a lower OG beer that finishes at the same FG.



#7 djinkc

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Posted 01 April 2015 - 04:46 PM

I should've said a FG of 1.000 is 100% attenuation, not 100% fermentation.

 

FG can go below 1.00.  ETOH has a lower gravity than water.  It would be a dry sucker though.



#8 3rd party JKor

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Posted 01 April 2015 - 05:15 PM

FG can go below 1.00.  ETOH has a lower gravity than water.  It would be a dry sucker though.

 

 

Yes, and your attenuation would be over 100%. 

 

Some really good linkage HERE.



#9 matt6150

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Posted 14 May 2015 - 05:53 PM

I wanted to expand on this thread a little. What started it is that it seems I'm not getting the highest attenuation that I should. So I wanted to hear from you guys some bullet points on what things are essential for getting the best attenuation out of yeast? Just overall good practices, maybe I'm just over looking something. It might be a combination of things.



#10 neddles

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Posted 14 May 2015 - 06:03 PM

None of this will be too revolutionary for you Matt but the things I think of are...

 

1. Appropriate size pitch of healthy and fresh yeast.

2. Sufficient O2.

3. Rising temperature fermentation schedule.

4. Minimize unfermentables with both grist composition and mash temperature. (need accurate thermometer)

5. Yeast selection.

6. A dose of nutrient probably doesn't hurt.

 

I'm probably leaving something out here but others will fill in the blanks I'm sure.



#11 matt6150

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Posted 14 May 2015 - 08:08 PM

None of this will be too revolutionary for you Matt but the things I think of are...

 

1. Appropriate size pitch of healthy and fresh yeast.

2. Sufficient O2.

3. Rising temperature fermentation schedule.

4. Minimize unfermentables with both grist composition and mash temperature. (need accurate thermometer)

5. Yeast selection.

6. A dose of nutrient probably doesn't hurt.

 

I'm probably leaving something out here but others will fill in the blanks I'm sure.

Well I feel I am doing all of those things. The decline in my attenuation started right after I started using my new system. So I have been thinking it is mainly mash temp. I have double/triple checked with multiple thermos, including a thermapen, and the probe/pid combo looks to be right on. Maybe I just need to mash lower overall to achieve the same results as I have before. I started using a aeration system right around Christmas. I give it a 45-60 sec blast of O2 out of those red bottles. I have tried dozens of yeast including dry. I think its getting better and really I'm not that far off from the manufactures percentages. Sometimes it maybe right on the low end and sometimes below, but always seem to make good beer with no sweetness as far as I can tell.



#12 neddles

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Posted 14 May 2015 - 08:36 PM

Well I feel I am doing all of those things. The decline in my attenuation started right after I started using my new system. So I have been thinking it is mainly mash temp. I have double/triple checked with multiple thermos, including a thermapen, and the probe/pid combo looks to be right on. Maybe I just need to mash lower overall to achieve the same results as I have before. I started using a aeration system right around Christmas. I give it a 45-60 sec blast of O2 out of those red bottles. I have tried dozens of yeast including dry. I think its getting better and really I'm not that far off from the manufactures percentages. Sometimes it maybe right on the low end and sometimes below, but always seem to make good beer with no sweetness as far as I can tell.

I don't remember how your system works. Does your wort recirculate through something that is significantly hotter than the rest of the mash that might effect the enzymes? 

 

In the end if you are liking the way the beer is turning out maybe it's nothing but an interesting observation.



#13 Brauer

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Posted 15 May 2015 - 04:00 AM

Well I feel I am doing all of those things. The decline in my attenuation started right after I started using my new system. So I have been thinking it is mainly mash temp. I have double/triple checked with multiple thermos, including a thermapen, and the probe/pid combo looks to be right on. Maybe I just need to mash lower overall to achieve the same results as I have before. I started using a aeration system right around Christmas. I give it a 45-60 sec blast of O2 out of those red bottles. I have tried dozens of yeast including dry. I think its getting better and really I'm not that far off from the manufactures percentages. Sometimes it maybe right on the low end and sometimes below, but always seem to make good beer with no sweetness as far as I can tell.

That does seem low.  For reference, I looked up WLP002, which states 63-70% attenuation. I then checked a couple recipes at each of a few different mash temperature that I fermented with that yeast, and I got 72% attenuation when mashed at 155F, 75% when mashed at 152F, and and 77% when mashed at 150F. I couldn't find any that were down in the manufacturer's range.

 

If you like the beer, it doesn't matter, but there are some things you could try. You can try lower mash temperatures, If you want to get more attenuation. Also, try swirling the wort after bubbling the O2 in, with the bung in. It's hard to beat that combination for getting the most O2 dissolved. 

 

I don't remember how your system works. Does your wort recirculate through something that is significantly hotter than the rest of the mash that might effect the enzymes? 

 

In the end if you are liking the way the beer is turning out maybe it's nothing but an interesting observation.

Good question. That would effectively make the mash temperature higher. I suppose that circulating hot water through the mash, directly firing the mash, or very hot infusions might tend to destroy enzymes locally and account for some of the subtle variability between systems.



#14 3rd party JKor

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Posted 15 May 2015 - 07:15 AM

I agree with Brauer, seems low.  I'm almost always at the top end or above the Mfg. attenuation range.

 

How's your water?  Sufficient calcium?

 

You went to a 'new system', what does this entail?  What are the difference from the old system?



#15 matt6150

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Posted 15 May 2015 - 07:29 AM

I don't remember how your system works. Does your wort recirculate through something that is significantly hotter than the rest of the mash that might effect the enzymes? 

 

In the end if you are liking the way the beer is turning out maybe it's nothing but an interesting observation.

 

 

I agree with Brauer, seems low.  I'm almost always at the top end or above the Mfg. attenuation range.

 

How's your water?  Sufficient calcium?

 

You went to a 'new system', what does this entail?  What are the difference from the old system?

System is a EHERMS. It recirculates through a coil but it is not hotter at all. The old system was a cooler and kettle, batch sparge. The only part I wonder about is after my mash of 60min I raise the temp on the PID to mashout. Well it takes awhile(15-20min) for the wort to get up to temp but the temp in the HLT only takes about 5min.

 

My water is really low on all numbers but I build it up for every batch. Calcium is about 50ppm for every batch.



#16 HVB

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Posted 15 May 2015 - 07:40 AM

Matt,

Any other changes other than the system like grain type or manufacturer?



#17 matt6150

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Posted 15 May 2015 - 07:57 AM

Matt,Any other changes other than the system like grain type or manufacturer?

No, been using mostly CMC for years now for the basics, 2-row, pils.I will add that I did get 79% on my last batch mashing at 148 for 90 min and a packet of S-05. That batch was also split with WLP644, but that carboy is only down to 1.020 from 1.070 in about 2 weeks. I made a starter for the 644 but it was a older vial. I did step it though.

Edited by matt6150, 15 May 2015 - 07:57 AM.


#18 HVB

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Posted 15 May 2015 - 08:05 AM

No, been using mostly CMC for years now for the basics, 2-row, pils.I will add that I did get 79% on my last batch mashing at 148 for 90 min and a packet of S-05. That batch was also split with WLP644, but that carboy is only down to 1.020 from 1.070 in about 2 weeks. I made a starter for the 644 but it was a older vial. I did step it though.

So we have opposite issues.  I have lower"ish" efficiency but good attenuation.



#19 matt6150

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Posted 15 May 2015 - 09:02 AM

So we have opposite issues. I have lower"ish" efficiency but good attenuation.

Yeah I get around 95% efficiency.

#20 HVB

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Posted 15 May 2015 - 09:04 AM

Yeah I get around 95% efficiency.

grumble ... grumble .. grumble :stabby:




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