3rd BIAB; Problems...one with efficiency, and question

Brewed my 3rd BIAB yesterday. Was very concerned about the volume I was able to transfer to my fermenter so measured it today. Discovered today that my Bayou Classic brew kettle's gallon measurements (which came pre-marked) are not accurate. (At 5 gallon - off by 0.2 gallon, and at 14 gallon - off by 0.5 gallon). So at 5 gallons it was at the 4.8 gallon mark, and at 14 gallons it read 13.5 gallons. So this meant I put too much water into my wort at the start, and my measurements were off... Corrected them today.

This is beer I was working with here: http://www.biabrewer.info/viewtopic.php?f=7&t=3208

For the first time ever I took a gravity reading prior to boil. It was supposed to be at 1.039 and it was at 1.035. This is likely as a result of having more water in the pot than I was supposed to, because of the wrong markings inside the pot. (Suggestion that if you have markings inside your pot, may want to check them to make sure they are accurate.) I was very concerned about ending with a way too low FG, so was happy to see it come very close (1.051 FG instead of 1.052 in the plans). But why so much evaporation (??? apparently) compared to what the BIABacus says I should have?

QUESTIONS:
1) On the BIABacus, it estimated the EBC at 7.0. Very curious when I had 10 lbs. of Pilsner malt with EBC of 4.0 and 5/8 lb. of CaraPils with EBC of 4.8, and how do those added together get something that much darker in color...? Not understanding the math on this...for the calculation. Not sure why it can make things this dark.
2) Why am I getting so much more evaporation (apparently), than what the BIABacus says I should get? Noticed this in BIABs #1 & 2 as well, seemed to have more evaporation than what it shows that I should. 90 minute mash + 10 minute mash-out + 90 minute boil...plus transition time when raising temperatures. Not sure what I'm doing wrong.
3) Efficiency - appears to be fairly low. Wonder why?
3-A) The thermometer was new at Christmas, and when boiling appears to be accurate (at least within 1 degree of 212 deg F (0 C) when boiling). Most of the boil I was hotter than that, like 215-216 deg F or so...
3-B) Recipe called for mashing for 90 min at 154 deg F (67.8 deg C). With looking at my notes, temp was as high as 155 deg F, and was at 150 deg F when I started raising the temperature for a mash-out.
3-C) NOTE: My efficiency into Fermenter looks great, but that is really because of the markings I thought I was way low and so dumped most everything into the fermenter, feeling the hot break stuff would just settle out as trub at the bottom of the fermenter and I would get some more beer out of it...).
4) IBUs @ Pitching number shows 43.4. Is that final? Wonder why...because the plans had IBUs at 38.9. So does that mean this be an almost too hoppy Czech Pils...?
5) Mash-out supposed to be at 170 deg F (76.7 deg C). If Mash-Out gets to 172 degress when it starts and finishes at 170 - which is what happened - does that cause a problem?

Guess the two biggest questions of the above are Evaporation & Efficiency. If anyone has any input on any of these questions, thanks in advance... New BIAB'er, and probably most of these are silly questions.

Thanks,
Scott

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Good questions Scott and Josh has given far briefer answers than I ever could ,

I'll add a couple of things.

1. Google the Morey equation.

2. Your evaporation figure is also relying on two numbers that are hard to measure - VIB and VFO (see Clear Brewing Terminology). It is easy to mis-measure either of those but this is probably not your problem as you said you had noticed this on your prior brews. The BIABacus evaporation estimate is based solely on kettle diameter collected from about forty brewers. As Josh mentioned, there are many other factors that come into play. If you are consistently getting high evaporation rates then over-ride the default by using Section X. Also note that evaporation will vary greatly from brew day to brew day especially if you brew outdoors.

3. Your efficiencies are fine. Your EAW is dodgy because you have not recorded a KFL in Section L.

4. Don't even worry about that.

5. All's good.

...

Above you mentioned FG. FG is actually the gravity after your beer has fermented (final gravity). What you were referring to was OG or the original gravity (gravity at pitching). A lot of brewing terminology is really confusing. Your questions however are not .

PP

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Thank you, Joshua and PP.

I can understand that boiling off water will concentrate and thus darken the remaining wort. That makes sense. But "The Morey Equation" was a little confusing with what is apparently "linear regression"... (Don't remember what that is, Business Calculus was 25 years ago...). Oh well, I got the idea and it helps. Thanks.

On evaporation...think I will brew a couple more times before making changes. First BIAB brew day in late December was just above freezing and Saturday was pretty windy, and I do brew outside... Maybe in summer Boil Off Rate will closer match what is in the BIABacus.

Misspoke on the OG / FG thing. Oops. New to BIAB and whole grain brewing but have done extract brews for some years. Your Clear Brewing Terminology is great (a lot of new terms to memorize and that will take time). The BIABacus is very helpful... Seemingly helps to make a complex operation much more manageable. Still learning it too, but it is much easier to understand now than 2 months ago. Been learning lots of things through you gentlemen and this excellent website which "should" result in more consistent and better beer over time (even if it is impossible to have homebrews be truly consistent).

Thanks again for all your help!!!

Scott

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Okay, just kegged the Czech Pilsner tonight... It attenuated further than I was expecting. OG was 1.051 and FG 1.011. The FG is lower than what the official "range" is for Czech Pilsner according to the Brewing Classic Styles book.

Fermentation was on the warmer side of what things were supposed to be. Kept it at 53-54 degrees F for first 2 days (about 12 deg C). 54 to 56 deg F (12-13 deg C) for the next 9-10 days. Then 56-58 deg F (13-14 deg C) for the next 3 days so. Then took it inside for a D-Rest, and warmed from 58 deg to 65 deg F (14 to 18 deg C) over final 3 days.

Unseasonably warm here in Oregon, and looks like I brewed this at the final time I could possibly have done it without a fermentation chamber. Wonder why my FG wound up low?

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Scott, another thing with the FG is that given everything else is equal, a batch with a lower OG (i.e. lower grain bill) will result in a lower FG. So, your lowering of the grain bill will have had an effect. Secondly, a single FG reading can't be recorded as gospel so don't place too much weight on it.

In your BIABacus, in Sections C and D, there is no need to right anything on the right hand side unless it differs from the left. For example, there is no need to re-write the same EBC reading on the right of C or the hop names and times on the right of Section D.


PP

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Scott, theoretically, I suppose you could check the FG again after carbonation but you'd have to make the beer go flat again and during that process, you'd have to be careful to not lose any volume by evaporation. Not sure how you do that?

But, I think the real answer here is what Rick mentioned above. At this stage of the brewing process, you really can't do anything to change anything so you should have zero focus on numbers until you taste the beer. If it tastes fine, then there is nothing to worry about. If something doesn't taste right, then numbers are just one of many tools that might help you find a problem.

Numbers are brilliant tools when used in the right way. Good numbers will help you make a great brew plan and help you predict your final outcomes but you should never expect your final outcomes to be exact as so many variables come into play. Commercial and craft breweries go to great lengths to deal with these natural variances that occur on each batch. They do not expect to hit numbers dead on (let alone flavours and aroma) without having to make adjustments on each and every batch. Many craft breweries, no matter how good they are, even after adjustments, will have different number, taste, flavour and aroma outcomes on each batch, often considerable ones.

Use the clever numbers/intelligence of the BIABacus to set your brew up but never think you have done something wrong when the final numbers don't fit perfectly.


PP

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