10 replies to this topic

[OhioMurb]

Still working on this AG thing and I'm looking at my efficiency.For 3 batches, according to Beersmith, my "efficiency into boiler" has consistently been in the mid-70's. But my "brewhouse efficiency" which is calculated with post-boil numbers, is in the mid-60's.So, does this tell me that my mash setup is relatively efficient, but somehow my boil process is not? My pre-boil gravity is usually spot on to the estimate, but my OG is usually lower than the estimated OG. Could it be that my boil is not vigorous enough to evaporate off enough water and raise the gravity?

[MtnBrewer]

Still working on this AG thing and I'm looking at my efficiency.For 3 batches, according to Beersmith, my "efficiency into boiler" has consistently been in the mid-70's. But my "brewhouse efficiency" which is calculated with post-boil numbers, is in the mid-60's.So, does this tell me that my mash setup is relatively efficient, but somehow my boil process is not? My pre-boil gravity is usually spot on to the estimate, but my OG is usually lower than the estimated OG. Could it be that my boil is not vigorous enough to evaporate off enough water and raise the gravity?

Boiling neither adds nor removes sugar and therefore cannot affect efficiency. Brewhouse efficiency is always less than mash efficiency because you will lose wort in the kettle deadspace.

[OhioMurb]

But doesn't removing water (evaporation) from the wort concentrate the sugars in solution? I thought gravity was a measurement of sugars in solution - is that not right?And the lost wort in this calculation isn't lost to the kettle - it's lost to evaporation.

[MtnBrewer]

But doesn't removing water (evaporation) from the wort concentrate the sugars in solution? I thought gravity was a measurement of sugars in solution - is that not right?

Yes it does but since it doesn't add or remove any, it doesn't affect efficiency. Gravity is only the density of the liquid or in other words, the concentration of sugar to water. You can evaporate water until you're left with syrup and there's still the same amount of sugar in it.

And the lost wort in this calculation isn't lost to the kettle - it's lost to evaporation.

No, you don't lose wort to evaporation, only water. No sugar is lost in boiling. The loss I was speaking of is wort lost in the kettle deadspace, grant, hoses, etc.

[stangbat]

I just got done typing this somewhere else. Figure I'll share it here too.When most people on the forum discuss efficiency, they are talking about efficiency into the boiler. I.e., how efficient you were with your conversion during the mash and how well you lautered and sparged. Brewhouse efficiency also takes losses into consideration such as deadspace in the kettle, losses to trub, losses to hops, etc.Efficiency into the boiler can change based on the amount of grain in your tun (it is easier to get a good rinse with less grain), your sparge technique and rate, whether you do a mash out, how you maintain your mash temps, etc. Brewhouse efficiency can change based on how much hops you use, whether they are pellet or whole, how much break material you get, etc.Most people find efficiency into the boiler to be most important because they are brewing to hit a desired gravity or gravity range for a style. Volume is a secondary consideration, and if you have more or less beer due to your brewhouse efficiency being slightly higher or lower, so be it.I finally have my system dialed in so that my efficiency into the boiler is in the low 80s. My brewhouse efficiency is in the mid 70s, and typcially ranges from 72-76. I mainly adjust my brewhouse efficiency based on how much and what type of hops I'm using, my other losses are pretty consistent between batches.I think the numbers you are reporting are reasonable for someone that is learning AG and working through the kinks and quirks of their system. My brewhouse efficiency was in the low to mid 60s when I started doing AG.

Edited by stangbat, 24 May 2009 - 02:47 PM.

[Jimmy James]

Efficiency is also going to be dependent on the actual yield of the grain lot(s) that you have and how accurate your measurements of grains and volumes are. My feeling is that efficiencies posted by others around the forums are not so much relevant as getting a feel for your own system like Stangbat posted. All the inaccuracies in your weights and volumes will hopefully be the same or similar each time, so you can trend your brewhouse efficiency and know if it's going up or down regardless of whether the number itself is accurate.

[djinkc]

I don't want to know my brewhouse efficiency. It probably sucks but I don't see how I could get it much better. I'm happy with what goes into the kettle though.For the OP, if you're missing your post boil gravity either boil harder/longer if your post boil volume (that makes it into the fermenter) is high. Or start with a larger volume preboil still at the same preboil gravity if your postboil volume (again in the fermenter) is low. It's nice to hit both gravity and volume. But if I had to settle for one it would be gravity.

[MtnBrewer]

Efficiency is also going to be dependent on the actual yield of the grain lot(s) that you have and how accurate your measurements of grains and volumes are.

No, efficiency is not dependent on yield. It is only dependent on your process. If you use a grain with a higher yield, you should extract more sugar but since efficiency is relative to to the yield of the grain it shouldn't matter. Put another way, efficiency is the amount of sugar extracted as a percentage of the maximum that you could have extracted. If the yield goes up, you would expect it to cause efficiency to drop. However you should extract proportionately more sugar from that grain and so efficiency will remain the same.

[BrewerGeorge]

No, efficiency is not dependent on yield. It is only dependent on your process. If you use a grain with a higher yield, you should extract more sugar but since efficiency is relative to to the yield of the grain it shouldn't matter. Put another way, efficiency is the amount of sugar extracted as a percentage of the maximum that you could have extracted. If the yield goes up, you would expect it to cause efficiency to drop. However you should extract proportionately more sugar from that grain and so efficiency will remain the same.

I thought he was talking about inconsistencies between the average grain yield in the programs vs the actual yield of individual lots. The discrepancy could cause a point or two of difference in the calculations.

[MtnBrewer]

I thought he was talking about inconsistencies between the average grain yield in the programs vs the actual yield of individual lots. The discrepancy could cause a point or two of difference in the calculations.

It could change what you calculate for efficiency if you use the wrong data (if you use a yield of 37 instead of 36 ppppg, for example) but it won't change the actual efficiency that you got.