Three questions after the first AG brew

[bredstein]

After 13 batches of extract and mini-mash brews, I finally made my AG conversion Today I brewed a nut brown ale (the recipe comes from internet). The only issue I ran into was that it started raining about 10 minutes after I put the kettle on fire - so I killed the fire to bring the burner inside the house, and meanwhile put the kettle (a converted half-barrel keg) on the carpet, which melted all the way through in no time Anyway, here is the grain bill:

9 lbs 2 row US pale malt
1 lb crystal 60L
1 lb flaked oats
0.5 lb victory
0.25 chocolate
*******************
1 oz williamette @60 min
1 oz goldings @15 min
1 tsp irish moss @15 min
*******************
Nottingham Dry yeast

I used a 5 gal cooler, and there was enough room for 11.75 lbs of grain and 3.7 gals of mash water. I had it at 154F for an hour, stirred twice, and by the end the temperature dropped to 150F. Tested with iodine, it didn't change the color. Then I drained, returned some wort back into the cooler, drained more, and filled twice all the way to the brim, which made the total of 4.5 gallons of 178F water. Collected about 6.3 gallons.

Now, as the carboy sits happily in the fermentation chamber, I made my calculations and have there questions.

1) I read that the first runnings are cloudy and have to be returned. I followed this advice, but I cannot say that they were cloudy - it was a really thick solid dark brown color. I could not see anything there. Is it normal for brown ale? And what if you do not pour this first quart back into the cooler?

2) I was prepared to get a low efficiency for the first brew. However, my number seems to be not that low at all. Which makes me think that maybe there is some mistake on my side with math? Here is how I did it:
a) (9 x 37) + (1 x 34) + (1 x 33) + (0.5 x 34) + (0.25 x 34) = 425.5
b) 425.5 / pre-boil 6.3 gals that I collected = 68
c) my OG 56 / 68 = 82%
So what do you say, is this calculation correct?

3) The other question is about OG. The HBT wiki says that "the brewhouse efficiency will always be a few points lower than the mash efficiency." Well, I had 1.056 before boil and 1.058 after. I started with 6.3 gals and ended with 5.5 gals. What is the catch here?

 

[Yooper]

1. Vorlaufing (recirculating the first quart or two) is to get out the chunks of husks and grain. If you don't have any solids, then some cloudiness is fine.

2. I use software, but I come up with brewhouse efficiency of 72% if you have 5.5 gallons of 1.058.

3. That doesn't make sense. You can't have an OG of 1.056 with 6.3 gallons and then 1.058 with 5.5 gallons. That's not possible. One of the readings is incorrect. Did you cool the preboil reading to under 90 degrees before testing? Any reading over 100 degrees or so is worthless, and you can't rely on it. I think that's why your efficiency number is #2 is incorrect.

 

[bredstein]

3. That doesn't make sense. You can't have an OG of 1.056 with 6.3 gallons and then 1.058 with 5.5 gallons. That's not possible. One of the readings is incorrect. Did you cool the preboil reading to under 90 degrees before testing? Any reading over 100 degrees or so is worthless, and you can't rely on it. I think that's why your efficiency number is #2 is incorrect.

That is exactly my concern I am using a hydrometer from Austin. I check it once in a while in pure water, and it seems to be OK. This time I measured at 60 degrees - put the cup in the freezer for 5 minutes, then checked with a lab thermometer, it was 57, so I had to hold it in my hands for a few minutes...

 

[bredstein]

I use software, but I come up with brewhouse efficiency of 72% if you have 5.5 gallons of 1.058

OK, I see how it works. So which reading is more important, in other words, what should I measure next time - pre-boil or brewhouse?

 

[Yooper]

That is exactly my concern I am using a hydrometer from Austin. I check it once in a while in pure water, and it seems to be OK. This time I measured at 60 degrees - put the cup in the freezer for 5 minutes, then checked with a lab thermometer, it was 57, so I had to hold it in my hands for a few minutes...

Five minutes cooled it to 57? Wow, that's fast! Mine would take much longer to cool a sample. Did you shake it up a little, so it wasn't 140 degrees in one spot but 57 in another?

Oh, speaking of shake it up a little, did you stir your wort well before taking the sample for the preboil OG?

 

[Yooper]

OK, I see how it works. So which reading is more important, in other words, what should I measure next time - pre-boil or brewhouse?

Both! You want to know your conversion efficiency, and you want to know what your final post-boil. As an example, if you have preboil 6.5 gallons of wort at 1.056 and you boil off 1.25 gallons per hour, your post boil has to be 1.069 at 5.25 gallons. It has to be- that's the way it works.

There are some factors in the volume, like cooling shrinkage, that come into play but they really don't affect the actual volume and the actual OG beyond knowing that the wort will be 4% less when cooled than in the boil pot.

 

[Yooper]

One of the reasons the preboil gravity is so important is so you can fix things on the fly. For example, if you were expecting 1.060 preboil and you got 1.045, you can either adjust your recipe by lowering the hops, or boiling longer to reduce volume, or even by adding DME to get to where you need to be.

 

[bredstein]

Five minutes cooled it to 57? Wow, that's fast! Mine would take much longer to cool a sample. Did you shake it up a little, so it wasn't 140 degrees in one spot but 57 in another?

Oh, speaking of shake it up a little, did you stir your wort well before taking the sample for the preboil OG?

Well, it was only two or three table spoons - I am using the plastic tube that the hydrometer came with I stirred it with the thermometer real good, so I don't think I could have spots. And yes, I stirred the wort in the kettle also real good.

 

[diS]

One of the reasons the preboil gravity is so important is so you can fix things on the fly. For example, if you were expecting 1.060 preboil and you got 1.045, you can either adjust your recipe by lowering the hops, or boiling longer to reduce volume, or even by adding DME to get to where you need to be.

Great advice, this is one of the useful things to do pre-boil... especially if you are still getting know your system and your efficiency did not stabilized jet.

As for gravity reading, I' sure you miss-measured something, volume or OG.. did you counted shrinkage loss?

 

[bredstein]

As for gravity reading, I' sure you miss-measured something, volume or OG.. did you counted shrinkage loss?

I am not sure I understand your point - how can you "mis-measure" with such a primitive tool as a hydrometer which you just stick into the liquid and compare its position above the surface with a certain value? What does it have to do with any losses?

 

[duboman]

Well, it was only two or three table spoons - I am using the plastic tube that the hydrometer came with I stirred it with the thermometer real good, so I don't think I could have spots. And yes, I stirred the wort in the kettle also real good.

Unless I'm misunderstanding, how did you actually get a gravity reading with only 2-3 tablespoons of wort?

 

[bredstein]

Unless I'm misunderstanding, how did you actually get a gravity reading with only 2-3 tablespoons of wort?

I do not have a dedicated test cylinder, I am using a plastic storage tube which came with the hydrometer. It is just a little bit longer and wider than the tool itself. It is enough to fill it up maybe with 40-50% of its volume. Well, I'll better go and count tablespoons OK, it took exactly 6 tablespoons - my bad!

 

[duboman]

I do not have a dedicated test cylinder, I am using a plastic storage tube which came with the hydrometer. It is just a little bit longer and wider than the tool itself. It is enough to fill it up maybe with 40-50% of its volume. Well, I'll better go and count tablespoons OK, it took exactly 6 tablespoons - my bad!

Just trying to verify your hydrometer was actually floating

 

[Yooper]

I am not sure I understand your point - how can you "mis-measure" with such a primitive tool as a hydrometer which you just stick into the liquid and compare its position above the surface with a certain value? What does it have to do with any losses?

No, your volume! In order for the preboil gravity to have any meaning at all, you have to know your exact volume when you took the measurement.

If you had 1.056, but, say, 6.0 gallons instead of 6.3, that would make a huge difference.

There is a faulty measurement somewhere. Whether it's the volume, the preboil SG reading (probable, as it's just not correct to have the readings you did), the OG reading and volume, the temperature, etc, I do know not. It seems most likely to be an inaccurate hydrometer measurement, though- but the 6.3 volume to 5.5 finished volume also seems wrong. Generally you boil off at least one gallon an hour, often more. And then when you count shrinkage and so on, the volume measurements seem askew as well.

 

[bredstein]

If you had 1.056, but, say, 6.0 gallons instead of 6.3, that would make a huge difference.

I rely on the sight glass in my measurements. I calibrated it myself with a half-gallon juice bottle, I am quite confident in the pre-boil volume of 6.3 gallons...

the 6.3 volume to 5.5 finished volume also seems wrong. Generally you boil off at least one gallon an hour, often more.

I was also surprised, and the finished volume seems to be the best candidate for mistake. It did look as 5.5, but I could easily read 5 as 5.5, given that I do not have any digits on the glass, just stripes of electric tape What makes me think so was that I ended with less than 5 gallons in carboy, it was more like 4.7... and there was not much junk left on the bottom - I drained every drop.

Now if I go for the homebrew efficiency (not pre-boil) and play with both 5 and 5.5 volumes, here is what I am getting:
a) 425.5 / finish vol 5.5 gals = 77; my OG 58 / 68 = 75%
b) 425.5 / finished vol 5 gals = 77; my OG 58 / 68 = 68%

Much closer to what I expected Thank you for clearing that up for me!

 

[Brulosopher]

1. Don't worry about it, you're fine.

2. Don't worry about it, you're fine.

3. Don't worry about it, you're fine.

Cheers!

*Disclaimer* on my 6th beer of the night...

 

[Dynachrome]

I've been doing all-grain for a while. I have always had trouble with guessing how much loss of water I will get due to grain absorbing it. One gallon doesn't sound too far off for your size batch.

I don't know how important efficiency is to me. I guess if I'm not hitting my efficiencies, I'm wasting value for the grain I've purchased. However If I have an original specific gravity of 1.058, and I end up with a final gravity of 1.008, I can still calculate my ABV. ABV is a good thing to know sometimes.

 

[duboman]

I've been doing all-grain for a while. I have always had trouble with guessing how much loss of water I will get due to grain absorbing it. One gallon doesn't sound too far off for your size batch.

I don't know how important efficiency is to me. I guess if I'm not hitting my efficiencies, I'm wasting value for the grain I've purchased. However If I have an original specific gravity of 1.058, and I end up with a final gravity of 1.008, I can still calculate my ABV. ABV is a good thing to know sometimes.

You shouldn't have to keep guessing. Typical absorption is .125g/lb of grain or approximately 1g/10#.

Efficiency should be important because you want to be able to brew batch after batch and achieve the same consistency from one to the next. This makes brewing much easier and recipe creation/use much easier as well. NOt only mash/lauter but also total brewhouse, otherwise, every batch you brew is a crap shoot