Losing Efficiency Somewhere Between Lautering and the Boil...

So, I am losing about 7ish points of Efficiency in between my Sparging and the boil. Here are the specifics.


Into the Boil Kettle I had a Gravity of 1.056 with 7.55 Gallons of Wort. This relates to a pre Boil Efficiency of 80.71%. After the Boil I had 5.60 Gallons of Wort with an OG of 1.068. This realates to an actual Batch Efficiency of 72.70%. Only reason this bothers me is that when I first started AG'ing, I was getting an efficiency number of about 64%. I tweaked a few things, and I started getting around 80%. But ever since I have changed my Mash Tun, I have been getting lower and lower numbers with every batch. I know though that it can't have anything to do with the Mash tun as my Efficiancy numbers are on as far as Pre Boil. So then, WTF? Can anyone here explain to me as to shy I would be losing some efficiency during the Boil?

I am eager to hear the responses to this...aren't you using a coleman cooler with a copper manifold??

Are you using a pump, counterflow chiller? Big hop bills? How much sludge are you leaving in the kettle? It doesn't take much wort loss to drop efficiency.

Using a Coleman Extreme 58 qt Cooler with a Gravity fed System. My lauter manifold is Copper. Still t

hough, why would this matter when I am losing my efficiency during the boil? Not being a wiseass, just asking a non sugar coated question.

Well, that is really impossible... if you are boiling off nearly 2 gallons, you should see at least a 17-20 point increase in the hydrometer reading. I cannot see how you could have a lower percentage of sugars in the same vessel when all you are boiling off is water.

Again, I have never tried to calculate my EFF prior to the boil, so what do I know?!

You are either screwing up on one or both of your gravity readings, or one or both of your volume measurements. Like The Pol said, if you boil 7.55 gallons of 1.056 wort down to 5.6 gallons, you will have a gravity of 1.0755. Is your second volume simply how much beer actually makes it to your fermenter? If so, the difference in your efficiencies is the difference between mash efficiency and brewhouse efficiency.

Is the post boil # your intended Target?

I guess like others have said, I can't see any way of losing sugars during the boil. You have a solution of a certain concentration of sugars, then you boil off water and end up with a lower volume of solution with a higher concentration of sugars. The only thing changing is the loss of water. I can't imagine anything else like hops or irish moss soaking up all the sugars:cross:. If I were to take a stab at this, I would look at how you're getting the pre-boil vs. post-boil numbers before looking at losing efficiency during the boil.

Aside from the numbers, it sounds like your mash tun change might be causing some problems with extract efficiency. What was you your old mash tun design and what's the new one?

You will lose some efficiency during the boil to absorbtion by the hops and dead space in the kettle and any other equipment. Switching from pellet hops to whole leaf will increase this loss. I usually lose 4 - 5%, but with IPA's (and a bunch of whole hops), this can increase to 6 - 7%

-a.

If you're taking your gravity readings at mash temps and depending on the conversion calculators, be aware that they're off by a bit. It helps to cool your sample down to at least 100F, if not your calibration temp.

ajf said:

You will lose some efficiency during the boil to absorbtion by the hops and dead space in the kettle and any other equipment. Switching from pellet hops to whole leaf will increase this loss. I usually lose 4 - 5%, but with IPA's (and a bunch of whole hops), this can increase to 6 - 7%

-a.

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You aren't really losing efficiency, you are just noting the difference between mashing efficiency and brewhouse efficiency. We really just have to know if his final volume is volume in the fermenter, or volume in the boil kettle after the boil is done.

Some people see like 1% difference between mash and brew house efficiency but others lose quite a bit more due to all the reasons above. How is it NOT an efficiency loss? Confused. Lost wort is lost efficiency.

My final volume is the amount of Wort that winds up in the Fermenter. My Pre Boil Volume is the amount of Wort that winds up in the Boil Kettle before I fire it up. With this Batch, I used right around 7 ounces of Amarillo Hop Pellets. Maybe all those hops had something to do with it?

As far as the volume measurements being off, I know that the amount going into the Kettle is right as I have used the same Carboys with the same markings on them for going on 15 years. Also, the way that I take my measurements for the volume of Wort in the Boil Kettle is quite accurate also. So, I think that my volume measurements are on.

When I take a Hydrometer and refractor measurement, the Wort is cooled to about 65 degrees, then the measurements are raken. The refractor is calibrated before each measurement with distilled water, and the refractor and hydrometer are both at room temp (68ish degrees).

7oz of hops is quite a lot if you let them run loose in the pot. You likely lost at least a 1/2 gallon into the hops. When I use hop bags, I lift them up out of the wort and clip the bag to the side so it can drain and I end up with a softball sized wad of dry hop sludge.

Bobby_M said:

7oz of hops is quite a lot if you let them run loose in the pot. You likely lost at least a 1/2 gallon into the hops. When I use hop bags, I lift them up out of the wort and clip the bag to the side so it can drain and I end up with a softball sized wad of dry hop sludge.

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I also use a hop bag with a stick that runs along the top of my kettle. The Hop Bag hangs off the stick. Makes for easier Hop Additions then when I used to tie the Bag to the side of the Kettle. I use a pair of Barbecue tongs to squeeze out all the Hop Goodness from the Hop Bag prior to Sparging into my Primary.

Ok, then I'm totally stumped for you. We've ruled out all the ways you'd lose sugar. I can only assume a slight error reading the gravity. Try again next time and be super precise with OG and volume measurements.

Bobby_M said:

Ok, then I'm totally stumped for you. We've ruled out all the ways you'd lose sugar. I can only assume a slight error reading the gravity. Try again next time and be super precise with OG and volume measurements.

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I'm with you Bobby. I'm actually at the point where I'm going to remeasure my measuring stick. Do the whole gallon of water thing in the Boil Kettle again to make sure that I'm on.

I decided to revive this thread since I have the same question and am hoping someone has found an answer. I calculated my pre-boil efficiency to be up near 85%, but my post-boil efficiency was down at 77%. I know my readings are as accurate as I can get. I adjusted for temperature for all SG measurements, but for the volume measurements I did not adjust (doesn't matter much anyways since its off by less than a percent).

I had 7.33 gallons of pre-boil wort with an SG of 1.047 and 5.25 gallons of post-boil wort with an SG of 1.059. I adjusted the pre-boil SG to be based off of a volume of 5.25 and got an SG of 1.066. I then calculated the density of the two volumes, then multiplied by the volumes to get the total mass of the two measurements. I then found the total loss to be about 133 grams of sugar.

Now I don't have a great concept of how much 133 grams is, but would that be small enough to be found stuck to the sides of my pots and to my wort chiller? I don't see any other way I could be losing sugar. I am using maybe 1.5 oz of hops and I am pouring my wort into the fermenter through a strainer so all I am leaving behind is hop trub. I also am not spilling any.

Any ideas?

Tell us about your preboil reading- the temperature of the sample, and whether it was with a hydrometer or refractometer.

Well I brew in two pots. So I drained all of my mash/sparge water and mixed the two pots back and forth. I measured the two volumes and got 3.73 gallons and 3.63 gallons. I took a sample from each and chilled them in the fridge and proceeded to measure using a hydrometer when they were around 80 F. I got 1.047 (adjusted for temp) for both samples.

For the post-boil measurements, I measured volume in the fermenter and took out a sample to measure with the hydrometer.

Sorry for the off topic, but out of curiosity, what do you use to measure your volume that gives you two decimal places like that?

I haven't really bothered with significant figures in a long while (since high school chemistry). However, I am measuring my volume with a ruler. I have measured the diameter of the pot, the height of the pot, and the distance between the top of the liquid and the top of the pot. I just use the equation for the volume of a cylinder and those numbers I gave you are the numbers my calculator gives me rounded off to two decimals. My measurements for diameter and height probably have accuracy to an 1/8th of an inch while liquid distance measurement is accurate to a 1/4 of an inch. I would guess that my volumes probably have an error of (+-) 1 qt.

Ah, right, a ruler. Makes more sense than the spoon handle i use >.<

I debated using a spoon handle, and then measuring the spoon handle, I figured skipping the middle step would be easier . But yeah I am starting to work out significant figures in my free time but probably wont be able to work out the numbers for a day or so. I know thats not where I am loosing sugar because its a significant difference. Any ideas if this sugar could be accounted for on the sides of my pots?

Has anyone considered soaking the wrung out hops in a small amount of water to recover the lost sugars, then adding the water back into the wort??

I do big IPAs and always get something like 65% efficiency.

I was reading Kaiser's post about his wiki when I came across my issue. I read through the wiki and it was very helpful. However, Kaiser seemed to run across the same issue of efficiency loss during the boil as i did. Unfortunately, he did not know where it was coming from either. One person suggested that the hops might have absorbed it like you did, but here is what Kaiser has to say:

But that is not enough to make a difference. I'm missing about 100g from a 5.5 gal batch. The dried trub minus the hops was only 20g.

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https://www.homebrewtalk.com/f36/giving-brewhouse-efficiency-closer-look-79829/