56 replies to this topic

[JReigle]

How did you verify that your thermometer was accurate? If your calibration thermometer is also 2-3 degrees off in addition to the 1-2F of your main thermometer or so, then your 149-150F mashes could very well be @154-155F.If it were me, I would mash 5 degrees cooler and 20 minutes longer next time to see what happens and go from there.

[BrewerGeorge]

How did you verify that your thermometer was accurate? If your calibration thermometer is also 2-3 degrees off in addition to the 1-2F of your main thermometer or so, then your 149-150F mashes could very well be @154-155F.If it were me, I would mash 5 degrees cooler and 20 minutes longer next time to see what happens and go from there.

Not a bad idea. When troubleshooting, it's sometimes worthwhile to go to an extreme. Mash at 140F. If the results are as predicted, it means the mash is performing as expected and leads you in other areas.

[drewseslu]

You thinking of the copper thing?

Yup, copper poisoning of the yeast was my guess...but 5-10 minutes shouldn't yield this result. Ehh...my 1/50th USD.

[AspenLeif]

How did you verify that your thermometer was accurate? If your calibration thermometer is also 2-3 degrees off in addition to the 1-2F of your main thermometer or so, then your 149-150F mashes could very well be @154-155F.If it were me, I would mash 5 degrees cooler and 20 minutes longer next time to see what happens and go from there.

I verified it was 212 (actual 211) at boiling and then compared it to 2 other thermometers at room temp. I agree that there still could me something to your post....and may try it. Mash the next one at 145 or less.

Yup, copper poisoning of the yeast was my guess...but 5-10 minutes shouldn't yield this result. Ehh...my 1/50th USD.

I am not familiar with copper poisoning.....other than I thought it was bad for exposure during the fermentation process...not necessarily the brewing process. I also have a (pretty elaborate) copper manifold in my mash tun. Educate me. One thing that may be true is that between the roughly 8ft of 1/2" copper in my mash tun and a 50ft coil of 3/8" copper for my IM....there is a lot of surface area of tarnish taken off while I brew. MB

Edited by Mainelybrew, 12 May 2009 - 01:22 PM.

[djinkc]

Yup, copper poisoning of the yeast was my guess...but 5-10 minutes shouldn't yield this result. Ehh...my 1/50th USD.

I've got several coming up that I brewed with the IC in for the entire boil. I had a little mishap pulling out the hop bag to put the IC in late in the boil. So there were several all pellet batches that ended up being brewed that way - we'll see how well they attenuated....

[Jimmy James]

FG 1.020 from OG 1.068 using WL american lager yeast.

What temp did you ferment that one at?

[drewseslu]

Konertjm had an issue with under attenuation he attributed to the copper coil, I'll ask him about it soon.

[ncbeerbrewer]

I can't comment on the Copper idea I leave mine in for 15 minutes every time and never seen an effect from that. I would say the idea to mash a few degrees lower and if you can raise the temp of the beer near the end of fermentation too and see where that gets you too. I did the temp raising recently on an ALT beer that I brewed. Fermented at 60 degree got down to 1.016. Raised the temp to 65 degrees and in three days 1007 brought it down to 1.008. None the less plenty of good suggestions here and I am sure this problem of yours will get figured out too. Good Luck!!

[Genesee Ted]

Copper poisoning? I have never heard of this but there are many breweries with copper kettles that see no adverse reactions. Am I missing something? Anyway, my input would be mash lower and ferment higher.

[AspenLeif]

What temp did you ferment that one at?

I don't have temp control for fermenting, just brew lagers in the winter. When I pitched this one, it was 47 in the basement and by the end of the 8weeks in primary, the basement was 55ish.

Copper poisoning? I have never heard of this but there are many breweries with copper kettles that see no adverse reactions. Am I missing something? Anyway, my input would be mash lower and ferment higher.

There is a possibility here...as it could deal with surface area per volume wort. I just figured up the surface area between my manifold and IM chillerManifold = 225in^2IM chiller = 636in^2Total is 861in^2 or 5.98ft^2 per 11gal of wort....or 0.54sqft/gal wortDoing some quick math...say on a 21barrel copper conical fermenter (dimensions may not be accurate, but close) saying that it is a 5ft diameter vessel with a 4ft tall cone on the bottom gives you roughly 86sqft of surface area of copper touching 651gallons of worth...or 0.13sqft/gal of wort.My system is 0.54sqft/gal wort vs. 0.13sqft/gal wort...or 4.25x more surface area touched per gallon.So there is considerable more surface area of copper in my system vs. a commercial conical fermenter. Aren't the copper ones you see commercially used SS lined..or no? The other factor being...I would expect that there is a higher % of CuO2 in my system...vs a conical. I don't know if it's the CuO2 or just the Cu that more detrimental. If someone could answer that for me....what I could do is pre-soak my copper parts to remove the oxide.MB

Edited by Mainelybrew, 13 May 2009 - 04:49 AM.

[Stout_fan]

Getting back to the thermometer thing.If you are using a glass thermometer, two point calibration is OK.If it is a lab grade + 0.1°C unit, that's OK as well.HOWEVER, the kitchen grade cannot be calibrated at extremes, and believed to be within a fraction of a degree, despite how many decimal points the display has.What the thermistor probe is getting is called piecewise linearization.Points are on the curve, say 20°F apart. It's the areas between those points that fall off the curve.So if you are using the standard grade digital thermo, you need to calibrate at temp of usage.Since, I've beaten this point into the ground, I'll conclude with the "hope this helps" bromide.

[AspenLeif]

Getting back to the thermometer thing.If you are using a glass thermometer, two point calibration is OK.Since, I've beaten this point into the ground, I'll conclude with the "hope this helps" bromide.

Using at standard glass dairy thermometer.MB

[DownEastBrewer]

Other than Mainely's copper MT manifold, when I brew with him my copper IC is in my brew kettle for the same 5-10 minutes that his is. We also have damn near identical water and use just about the same water adjustments.I do not have the same higher finish issue. Just had a porter that went from 1.058 to 1.010Mainely, i would think it's either bad thermometer or the combined issues of you brewing consistently higher starting gravity beers, and fermeting them in the very low 60's.next time we brew, we'll swap thermometers in our MTs and see how close they read.

[realbeerguy]

I do run a tighter mash 1.15 to 1.35 at most. I do this for mostly for maximizing the sparge water volume running through the grains.MB

When I started AG, I ran 1.25qt/lb, and most of the beers finished higher than what I expected. Went to 1.5 qt/lb at a minimum and got better attenuation.

[AspenLeif]

When I started AG, I ran 1.25qt/lb, and most of the beers finished higher than what I expected. Went to 1.5 qt/lb at a minimum and got better attenuation.

How did the decreased sparge volume effect your efficiency? I guess the bigger question is How would mash ratio directly effect attenuation?? MB

[davelew]

How did the decreased sparge volume effect your efficiency? I guess the bigger question is How would mash ratio directly effect attenuation?? MB

Mash ratio affects the conentration of amylase enzymes, which changes the balance of fermentable to unfermentable sugars. It's not a huge effect, but it is measurable.This chart shows the effects of mash temperature and mash thickness on attenuation (using the same grist, yesat, pitching rate, fermentation temperature, etc.). As you can see, the mash temperature has a larger effect than the mash thickenss, but th mash thickness does change fermentability by a few percentage points:_____0.7 qt/lb___1.25 qt/lb___1.7 qt/lb140F___73.3%____76.1%_____76.2%150F___67.4%____71.2%_____69.7%155F___64.4%____65.0%_____65.3%

[AspenLeif]

Mash ratio affects the conentration of amylase enzymes, which changes the balance of fermentable to unfermentable sugars. It's not a huge effect, but it is measurable.This chart shows the effects of mash temperature and mash thickness on attenuation (using the same grist, yesat, pitching rate, fermentation temperature, etc.). As you can see, the mash temperature has a larger effect than the mash thickenss, but th mash thickness does change fermentability by a few percentage points:_____0.7 qt/lb___1.25 qt/lb___1.7 qt/lb140F___73.3%____76.1%_____76.2%150F___67.4%____71.2%_____69.7%155F___64.4%____65.0%_____65.3%

What is your source for that chart? Good information none-the-less. Is the 140F correct.....or should that be 145F?If my temp measurements are correct...the I would say that my standard mash falls in the middle of this chart at 71.2% for a 1.25qt/lb mash at 150. I don't have my brewing texts in front of me....what is the attenuation of my lager that mashed at 1.25qt/lb at 150....when it went from 1.068 to 1.020?MBMB

[realbeerguy]

How did the decreased sparge volume effect your efficiency? I guess the bigger question is How would mash ratio directly effect attenuation?? MB

I had been taught higher mash temp = less attenuation due to the more non-fermentable sugars created in the higher temp , thinner mash= more fermentable and dryer, less body. I'm not up on all the technical terms. For example: my Berlinner Weisse is mashed thin @ 145dF for a dry, fermentable wort approx 1.75-2qt/lb, while my Scottish Ale is thicker, 1.25 qt/lb @ 156-8 dF for more body. I think that if you slightly increased your water/grain ratio you would see an increase in attenuation.My efficency is typically in the 75-78% range no matter what mash thickness.

[shmgeggie]

Is there a big difference between daytime temps and nighttime temps in your basement? I like to ferment beer pretty dry and I used to have problems with high FG. One thing that helped was fermenting in an area where the temps were more stable. I think the temp swings were causing the yeast to poop out too soon. You can keep temps a little more constant by sticking your fermenter in a water bath. With the extra thermal mass, temps should stay closer to average.

[AspenLeif]

Is there a big difference between daytime temps and nighttime temps in your basement? I like to ferment beer pretty dry and I used to have problems with high FG. One thing that helped was fermenting in an area where the temps were more stable. I think the temp swings were causing the yeast to poop out too soon. You can keep temps a little more constant by sticking your fermenter in a water bath. With the extra thermal mass, temps should stay closer to average.

I would say no. It's pretty consistent.MB