why the poor post boil efficiency here?

[robbyice]

I got 64% out of this..., I was expecting 75%. what step am I doing wrong?

here is the malt bill

14# 2 row
2# munich
1# crystal 40
.5# victory
.5 crystal 120
3 oz chocolate

I used the barley crusher to mill my grains (credit card gap I guess) I used 1.5q per pound of malt in my mash tun with a false bottom and held 151F for 60 minutes. I vorloffed and drained very slowly into kettle. I heated sparge water to 177F and poured it into the Tun for my batch sparge. I stirred it for 1 minute and then let it rest for 10 minutes. I vorloffed and drained extremely slowly into kettle. I boiled for 90 minutes (a low boil, not extra vigororous.)

should I have boiled harder? should I have used hotter water in the batch sparge? should I have let the sparge sit longer than 10 minutes?

what could I have done here? I know its a lot of grain but I usually am 75-80% so im sure its not the degree to which my grains are milled or something like that...

 

[LandoLincoln]

We can't assess unless you post numbers about your pre-boil wort.

 

[robbyice]

I did not take readings before the boil.

 

[lumpher]

was it 5 or 10 gallons? a lower efficiency is to be expected at 5 gallons with that big of a grain bill, since the lower volume of water reaches sugar saturation quicker

 

[robbyice]

sorry. 5 gallon batch. It is an Imperial Red Ale. the numbers that I hit should make it 7.75% ABV
-still good enough for me, but I was hoping for 8.something ABV

 

[kh54s10]

Agreed, we need your preboil gravity. Expected OG and measured OG. A picture of the crush?

The only need to drain a batch sparge slowly is so that you don't suck the grainbed down compacting it and getting a stuck sparge. I start draining slowly then open the valve all the way. I also add the sparge, vorlauf, drain. I don't wait 10 minutes. I have not found that waiting makes any difference. It might even be argued that waiting will allow the sugars stirred into the sparge water might seep back into the grain. I don't know if this is true or not.

Hotter sparge water should not make any difference.

The other usual questions, are your thermometer and hydrometer calibrated?

 

[robbyice]

yes. my equipment is calibrated (thermometer) I use the hydrometer conversion digital ap on brewersfriend to get accurate as possible hydrometer readings...

how much do you think a vigorous boil vs. an anemic boil can affect the efficiency?

 

[eric19312]

should I have boiled harder?

Not sure you are thinking about efficiency the same way I do. If you mean mash efficiency then there should be no difference between pre boil and post boil effiency. All that will change by boiling harder or longer is the post boil volume (more boiling makes it lower) and post boil gravity (lower volume same sugars makes gravity higher).

The larger grain bill will reduce efficiency if you collect the same post boil volume as you would for a smaller grain bill for reason mentioned abov. To compensate you can either plan a longer/harder boil to boil off more water or plan for lower efficiency on the large bill. I normally do both...e.g. plan for 2 hour boil instead of 60 min boil and reduce expected efficiency 5% or so from normal (so end up with even bigger grain bill).

 

[theseeker4]

Agreed, we need your preboil gravity. Expected OG and measured OG. A picture of the crush?

The only need to drain a batch sparge slowly is so that you don't suck the grainbed down compacting it and getting a stuck sparge. I start draining slowly then open the valve all the way. I also add the sparge, vorlauf, drain. I don't wait 10 minutes. I have not found that waiting makes any difference. It might even be argued that waiting will allow the sugars stirred into the sparge water might seep back into the grain. I don't know if this is true or not

You are not going to have a net movement of sugar from the wort back into the grain. Dissolved sugars move down their concentration gradient, meaning from higher concentration to lower concentration. Your sparge water has no sugars in it before you add it to your grain, so sugars are only going to move from the water absorbed in the grain to the sparge water. Once the concentration is equal between the two, sugar won't move one way or the other any longer. Waiting longer is only going to give more time for the sugars to move out of the grain into the wort until the concentrations are equal, then it won't make any difference. Sugars will never move from the wort into the grain.

 

[LandoLincoln]

Not sure you are thinking about efficiency the same way I do. If you mean mash efficiency then there should be no difference between pre boil and post boil efficiency.

That's not really true. I get a 96% mash efficiency but 75%-80% brewhouse efficiency. I lose a lot of wort to my vessel deadspaces and tubing and whatnot.

 

[eric19312]

That's not really true. I get a 96% mash efficiency but 75%-80% brewhouse efficiency. I lose a lot of wort to my vessel deadspaces and tubing and whatnot.

I am pretty sure the way I think about efficiency is due to my exclusive use of Beer Alchemy to design recipes. There is only one efficiency number in BA...that is called mash efficiency. Once you have entered your grain bill, actual pre boil volume and actual pre boil gravity the mash efficiency is calculated. Not sure how that is different in Beersmith or other software. I normally get 78-80% which I interpret to mean the percentage of potential sugar I got into my brew kettle. Potential sugar would be how much sugar there would be if 100% of starch were converted to sugar based on the exract potential of the different malts.

Brewhouse efficiency I believe would be how much of the potential sugar gets into the fermentor and overall efficiency would be final package. I guess my overall efficiency would be 78% (mash efficiency based on pre boil volume and ) x 10 gal finished beer /12.5 gal post boil volume = 62.4%. Kind of depressing but I hit my target gravities within 2 points (usually right on) and always end up with 2 full kegs when its done.

 

[doug293cz]

I am pretty sure the way I think about efficiency is due to my exclusive use of Beer Alchemy to design recipes. There is only one efficiency number in BA...that is called mash efficiency. Once you have entered your grain bill, actual pre boil volume and actual pre boil gravity the mash efficiency is calculated. Not sure how that is different in Beersmith or other software. I normally get 78-80% which I interpret to mean the percentage of potential sugar I got into my brew kettle. Potential sugar would be how much sugar there would be if 100% of starch were converted to sugar based on the exract potential of the different malts.

Brewhouse efficiency I believe would be how much of the potential sugar gets into the fermentor and overall efficiency would be final package.

Correct. BeerSmith and Brewer's Friend use the same efficiency definitions.

Brew on

 

[doug293cz]

was it 5 or 10 gallons? a lower efficiency is to be expected at 5 gallons with that big of a grain bill, since the lower volume of water reaches sugar saturation quicker

The highlighted phrase is incorrect. You can never get enough sugar in a mash to reach saturation. At 151˚F, a saturated maltose solution contains 66.7% sugar by weight, which is equivalent to an SG of about 1.33 (ref: http://chestofbooks.com/food/science/Experimental-Cookery/Solubility-Of-Maltose-In-Water-gillis.html. Even at 70˚F a saturated maltose solution has an SG of about 1.20.

The lower efficiency is due solely to the fact that more grain absorbs more wort (that you can't recover during run-off.) For example: if you mash 10 gal of grain in 6.5 gal of water, and have 0.1 gal/lb apparent grain absorption, then you recover 5.5 gal of wort @ 77.82% efficiency. This means the total wort volume (BK + retained in mash) is 5.5 / 0.7782 = 7.068 gal (total wort volume is more than water volume because of dissolved sugar volume.) This means you have 1.568 gal of wort absorbed in the grain. If we increase the grain to 15 lbs and strike water to 7.0 gal, we will still collect 5.5 gal of wort, but the efficiency will only be 70.04% because now we have (5.5 / 0.7004) - 5.5 = 2.353 gal of wort absorbed in the grain.

Brew on

 

[doug293cz]

I got 64% out of this..., I was expecting 75%. what step am I doing wrong?

here is the malt bill

14# 2 row
2# munich
1# crystal 40
.5# victory
.5 crystal 120
3 oz chocolate

I used the barley crusher to mill my grains (credit card gap I guess) I used 1.5q per pound of malt in my mash tun with a false bottom and held 151F for 60 minutes. I vorloffed and drained very slowly into kettle. I heated sparge water to 177F and poured it into the Tun for my batch sparge. I stirred it for 1 minute and then let it rest for 10 minutes. I vorloffed and drained extremely slowly into kettle. I boiled for 90 minutes (a low boil, not extra vigororous.)

should I have boiled harder? should I have used hotter water in the batch sparge? should I have let the sparge sit longer than 10 minutes?

what could I have done here? I know its a lot of grain but I usually am 75-80% so im sure its not the degree to which my grains are milled or something like that...

Ran your grain bill and some assumed volumes thru a batch sparge simulator, and 75% mash efficiency would be achievable had you achieved a conversion efficiency of about 98 - 99%. In order to have a mash efficiency of 65%, your conversion efficiency would have to have only been about 84 - 85%, which is pretty low.

Extending your mash time should improve your conversion efficiency by allowing more of the starch to be converted to sugar. You can speed up conversion by crushing finer, which could eliminate the need to mash longer. You may also have mash pH out of range, which could slow down conversion, or limit attainable conversion.

Edit: Your sparging process looks sound, and is not the cause of your low efficiency. And boiling does not affect efficiency at all (unless you have massive boil-overs.)

Brew on

 

[eric19312]

Correct. BeerSmith and Brewer's Friend use the same efficiency definitions.

Brew on

Thanks

Tried Brewers Friend. It confirms the Beer Alchemy efficiency value is being calculated off what BF calls pre-boil efficiency. As you say unless there are significant boil overs pre-boil and post-boil efficiency should be same.

Brewhouse efficiency is a somewhat sad 64% but that again is how I brew to make sure I end up with full kegs and hit my gravity targets.

What doesnt make sense is the BF conversion efficiency calculation. I have no idea how to determine total water used..."how much mash water was used (do not count grain absorption or mash tun dead space." I fly sparge to my volume target and dump the rest of the runnings. Kaiser's chart linked below looks much more reasonable to use to calculate conversion efficiency. Not that I have ever used it but think I will go ahead and try next brew.

http://www.braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency#Determining_Conversion_Efficiency

 

[robbyice]

Ran your grain bill and some assumed volumes thru a batch sparge simulator, and 75% mash efficiency would be achievable had you achieved a conversion efficiency of about 98 - 99%. In order to have a mash efficiency of 65%, your conversion efficiency would have to have only been about 84 - 85%, which is pretty low.

Extending your mash time should improve your conversion efficiency by allowing more of the starch to be converted to sugar. You can speed up conversion by crushing finer, which could eliminate the need to mash longer. You may also have mash pH out of range, which could slow down conversion, or limit attainable conversion.

Edit: Your sparging process looks sound, and is not the cause of your low efficiency. And boiling does not affect efficiency at all (unless you have massive boil-overs.)

Brew on

I appreciate the time you spent checking on this for me. I will, in the future, give the mash a little longer rest to get full conversion on these big beer recipes. how long do you recommend? im sure I can hold 151 for at least an hour and a half in my cooler. again, appreciate the time you put into this response.

 

[doug293cz]

I appreciate the time you spent checking on this for me. I will, in the future, give the mash a little longer rest to get full conversion on these big beer recipes. how long do you recommend? im sure I can hold 151 for at least an hour and a half in my cooler. again, appreciate the time you put into this response.

If you have a refractometer, you can monitor the progress of conversion. Kai Troester published a table that estimates maximum possible mash SG based on mash water to grain ratio (ref: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Measuring_conversion_efficiency.)



If the wort SG in your mash is much below the target value in the table, then your conversion is not near completion. You should stir the mash before taking an SG sample.

Brew on