Do you like numbers? Monitor conversion efficiency in the mash

[Horseflesh]

Like many others, I am trying to improve my mash efficiency. It isn't bad at ~75-77%, but I know it could be better and I'm looking for any easy gains I may have missed. @eric19312 and @doug293cz turned me on to this cool Braukaiser article which shows you how to monitor conversion efficiency separate from lauter efficiency:

http://www.braukaiser.com/wiki/inde...ng_Efficiency#Measuring_conversion_efficiency

This is a really cool and simple technique that can tell you a lot about your mash. Basically there is a theoretical maximum SG you can expect based on the mash thickness. If you monitor the SG of your mash as it proceeds you can see if you're getting good conversion. The method, of course, makes a number of assumptions about extract potential and so on.

I have a recirculating E-BIAB system, and I mill at the LHBS. Their mill is set to .045, and so I double-mill. I know this isn't the best crush for my system, but it is what I have for now.

My mash thickness for this batch was 3.16 qt/lb meaning my SG at maximum conversion should be theoretically 1.042. Normally I do a 60 minute mash but with the above technique in mind I extended it to 90 minutes and took refractometer SG readings every 15 minutes.

15: 1.032
30: 1.038
45: 1.040
60: 1.042 (where I normally stop)
75: 1.043
90: 1.044 (1.042 via hydrometer)

(I have calibrated my refractometer and learned that from ~1.015 - 1.045 I should add 1 to the indicated value to make it match a hydrometer. That correction is in the above data. Worts can be different though, yadda yadda.)

I also measured the 90 minute mark with a hydrometer, and got 1.042. But even if the refractometer readings are not as accurate as I would like, it does clearly show that the gravity rises through 90 minutes, and so I haven't hit full conversion at my normal 60 minute mark. I now have to decide if an extra couple of points is worth an extra 30 minutes.

 

[RM-MN]

How much is your time worth? A cheap Corona mill will let you mill your grain finer and with the smaller particle size conversion will happen quicker and more completely. You don't even have to recirculate to get higher efficiency. My mashes are more efficient than yours and I stop the mash at 30 minutes.

 

[pricelessbrewing]

This is a really good method to evaluate your crush. You just have to make sure you stir well before pulling a sample, and should always cool the sample to the reference temp of the hydrometer.

By charting the SG, or better the conversion efficiency, then you can tell how well the mash is going.

My rule of thumb is if you're not hitting ~90% conversion at 45-50 minutes, then you should take a look at your crush, mash pH, and dough in method.

 

[Horseflesh]

I'm 99% sure that crush is my main issue because I always hit my pH target, generally have a loose mash, and never see evidence of dough balls. I have to decide if I should mitigate the poor LHBS crush or just live with it.

If I hadn't done the test I wouldn't have known that I can pull out an extra couple of points with a longer mash, and that may be handy for doing big beers. Sometimes every point counts!

 

[DurtyChemist]

I have my own mill set to 0.037” and I’m hitting 75% mash efficiency calculated by beersmith and 70% brewhouse efficiency so I’d LOVE to get 90+% mash efficiency and 75-80% brewhouse.

 

[Horseflesh]

I would definitely try this conversion efficiency check, and extend your mash an extra 30 minutes at least when you do so. Then you will know for sure if you have problems with conversion, lautering, or both.

 

[schematix]

This is really a highly, highly underrated procedure. Within the last half year or so I rediscovered that article and really understood its significance so I started doing it after every mash step. I just pull a sample into a small beaker, throw in in the freezer, and about 10-15 mins later come back to record pH and gravity in Brix. It's actually quite enlightening to see the minute changes that occur in the mash past the often quoted 60 minutes. It can also help you understand if you need to change your game plan mid-mash and perhaps give it that extra 30 minutes until the grain has given it's all. FWIW i actually haven't seen a big difference due to crush. I've seen more differences due to the temperature steps employed.

One thing additionally to highlight from the procedure is the separation of what is typically treated as a single variable in all grain brewing - mash efficiency. There is a lot of knowledge to be gained by separating this into the conversion efficiency (the amount of sugars released into the wort, where 100% is actually achievable), and lauter efficiency (which is a measure of how much of the liquid you lose to the grain and dead space). The combination of these two are typically used by home brewers, but they are in fact quite distinct and each gives you it's own perspective on where system losses are, what can be gained, and what can't be gained.

 

[doug293cz]

This is really a highly, highly underrated procedure. Within the last half year or so I rediscovered that article and really understood its significance so I started doing it after every mash step. I just pull a sample into a small beaker, throw in in the freezer, and about 10-15 mins later come back to record pH and gravity in Brix. It's actually quite enlightening to see the minute changes that occur in the mash past the often quoted 60 minutes. It can also help you understand if you need to change your game plan mid-mash and perhaps give it that extra 30 minutes until the grain has given it's all. FWIW i actually haven't seen a big difference due to crush. I've seen more differences due to the temperature steps employed.

One thing additionally to highlight from the procedure is the separation of what is typically treated as a single variable in all grain brewing - mash efficiency. There is a lot of knowledge to be gained by separating this into the conversion efficiency (the amount of sugars released into the wort, where 100% is actually achievable), and lauter efficiency (which is a measure of how much of the liquid you lose to the grain and dead space). The combination of these two are typically used by home brewers, but they are in fact quite distinct and each gives you it's own perspective on where system losses are, what can be gained, and what can't be gained.

Hear! Hear!

Brew on