Questions...boil time, efficency...etc.

[Jhoss]

Hi Guys - I respectfully submit questions to the experts. I sure do appreciate all the info that is disseminated here on HBT. Scenario and questions...

Ran an all-grain brew this past Sunday. Trying out my new 10gal. round rubbermaid false bottom MLT. Boiling in a 9 gal. pot.

13 lbs of grain total:
10lbs US 2 row
2lbs Vienna
.5lbs Dextrine
.5lbs Caramel 20

Mashed at 150 ish for 75 mins. Fly Sparge for about 65 minutes.

Pre-boil amt. 6.8 gals, I was shooting for more but the
last runnings,was running very clear so decided to stop and measure...corrected gravity of 1.017. (Need Refractomer!) Post boil 1.054After cooling (need refractomer)..sucks! Should've/would've loved 1.062 - And I've obtained this before with a Zapapap. Missed OG by at least 8 pts.

Calculations for efficiency.

My impressionotential points of a batch = pts. X weight / Volume in gals.........Brewblogger says Pre-boil Volume so thats what I used in calculations.
Potential Pts. for grain types:
US pale 2 row...36
Viena...36
Carapils/dextrine..33
Caramel/crystal 20..35

10 lbs US pale 2 row, 10 X 36 / 6.8 = 52.94
2 lbs Viena, 2 X 36 / 6.8 = 10.58
.5 lbs Carpils, .5 X 33 / 6.8 = 2.42
.5 lbs Caramel 20, .5 X 35 / 6.8 = 2.5

Potential pts = 68.47, Brewblogger says 65.53. Beersmith calculated brewhouse efficiencies at 72% total, 63% measured...Brewblogger says, 74.61.
My Brewhouse Efficiency = Measured SG / Potential; 1054/1068.47...or...54/68 = .79

So, I calculate .79 by hand. Beersmith .72 or .63 (which is which)?..and Brewblogger at .75...lots of difference here....what gives?


About Boil time: If I had boiled longer I would have would have upped my OG. Doesnt seem like beersmith calculated specific gravity changes based on boil off eh?

Just getting used to new MLT, and functionally it worked great/nice and easy.

My sugar extraction efficiency needs to get better...I thought the crush looked good, not great, same as always from the lhbs...what else?

 

[ajf]

To make meaningful efficiency calculations, you need to take the gravity reading and volume at the same time.
i.e. You need the pre-boil gravity and pre-boil volume which could be used to calculate the mash/lauter efficiency, or the volume in the fermenter, combined with the gravity in the fermenter to calculate brewhouse efficiency.
Your calculation (79%) is based on the post boil gravity but the pre-boil volume. I would guess that the .72 and .63 figures relate to mash/lauter efficiency (72%) and brewhouse efficiency (63%); and the Brewblogger figure is the equivalent of the Beersmith 72%, but why they are 3% different, I don't know.

Hope this helps,

-a.

 

[Jhoss]

My preboil volume was about 6.8 gallons.
The corresponding preboil gravity showed 1.042, but it was hot. How hot? I'm not real sure. The last of the runnings was 134F - but the whole pot? I don't know - I didnt check it as I was getting ready to just boil it. I'd guess maybe 100F for the whole 6.8 gals. Which would be corrected to 1.048. That would mean the 1.3 gallons boiled off....would have only gotten me from 1048 to 1054....6 lousy points. Somethings wrong I guess. Well, It seems wrong to me.

 

[duboman]

Without getting into all the math the first thing you need to do is verify the quality of your crush since you are not milling your own grain. My experience with most LHBS is their crush is usually more coarse than optimal. Second, evaluate your sparge technique, fly or batch, are you stirring well? These two things should improve your efficiency for sure!

 

[tre9er]

You can figure out your preboil gravity by using your OG and final volume then figuring out what preboil gravity would have been at the higher volume.

Mash efficiency is the efficiency of the mash itself, ie. how much sugar was present in the grist after mashing. Brewhouse efficiency includes your lautering efficiency, ie. how much sugar you rinse from the grains (some will always be left behind).

 

[Yooper]

Remember that any hydrometer readings over 100 degrees are totally useless. Next time, have a pitcher of ice handy and chill your sample to under 100 degrees, then take a reading and use temperature correction tables or software to get the corrected reading.

Hydrometers are great, but a sample over 100 degrees is notoriously inaccurate, even with temperature correction tables.

In order to figure efficiency, you need an exact reading from the hydrometer, as well as the exact volume.

 

[Jhoss]

You are all confirming my thoughts. Refractomer on order (has shipped), which will prepare me well for my upcoming Labor Day brew. @duboman, I'd like some details on how to evaluate the crush. And my LHBS man is flexible - I asked him about the crush when I bought the grains - he said "hey -Ill give you flour if thats what you want" - that's not what I want but are there some kind of guidelines? If it's a crush issue - That would be an easy fix.

On Sparging: I fly sparge a quart at a time pouring onto a colendar like device slightly above the water surface which I try to keep from ever moving / the water level stays at the same level from start to finish. I don't shut down the outflow once I start and drain about 1 qt per 1.5 minutes..its pretty slow. Sparge water at 170F.

On Stirring; this happens twice, at dough in and 35 minutes into mashing, which i let go for 75 mins.

 

[tnlandsailor]

The other thing about efficiency is the actual potential of the grains you are using. If the grain is old, or was stored poorly, this can reduce what it will give you regardless of your system efficiency (you can't get blood from a turnip). Different malsters can also make a difference (I have had lower extractions with Briess malt in the past). Crush can have a huge impact on extraction. In my own brewing, I noticed that the first pass through my mill crushed the grain, but left most of the kernels intact. The kernels were crushed, but they were still mostly inside the husk. You really need to completely shed the husk on all of the kernels in order for the mash water to get at the kernels. I have found that a second pass through the mill on the same setting (mine is about 0.048 - 0.050 using a feeler gage) works well.

Fly sparging will definitely give you your best extraction of all the sparge methods. 6 minutes per gallon on your sparge speed sounds about right.

You definitely want to cool your samples to below 90 F. At 90 F, your correction is +4 points. It's better to get it to about 70 F if possible (+1 correction). The refractometer is probably a good idea, although I'm still using my hydrometer after all these years.

There is a good write up on efficiency and the factors that affect it here:

http://handsonbrewing.com/2012/02/the-efficiency-myth/

 

[tre9er]

I would stir after the mash is done, too...personally. Then vorlauf and start fly sparging.

On the crush, you want to see the endosperm of every grain, at least I do. Don't worry about "shredded husks" as long as you have enough large particles to form a lauter bed (ie. after vorlaufing a few times the wort runs clear).

 

[tre9er]

There is a good write up on efficiency and the factors that affect it here:

http://handsonbrewing.com/2012/02/the-efficiency-myth/

Good points here about the potential extract for the specific grain you're using (which can vary from brand to brand). Best to use what's listed by that maltster exactly. I haven't been doing this and for some reason it never crossed my mind until now.

 

[Jhoss]

A least I'v got a couple of things in mind now. Double grinding at the lhbs seems like a good thing to try. Maybe I read too much about the quality of the grind here, but I inspected the last batch and I was thinking it looked course, not too course but if I had to lean one way or another, more crush wouldn't hurt. That thought was quickly put aside as I remember hitting good numbers on the exact same recipe and grind from the same shop - if they had'nt changed the settings on the grinder....hmmmm. A grain mill is creeping onto my list.

Stirring. Really, stirring before running off....hmmm. This one is intriquing. I was thinking about all that settleing going on during the last 40 minutes of the mash setting me up a good filter on top of the false bottom - but the false bottom is there for a reason - to filter! So, I gotta try this. Seems like a good agitation at that time would liquify up some sugar that maybe would stick to the grain without it...couldn't hurt, might be a wicked improvement.

Good stuff all - thanks a tun. (Pun intended)

 

[tre9er]

Stirring. Really, stirring before running off....hmmm. This one is intriquing. I was thinking about all that settleing going on during the last 40 minutes of the mash setting me up a good filter on top of the false bottom - but the false bottom is there for a reason - to filter! So, I gotta try this. Seems like a good agitation at that time would liquify up some sugar that maybe would stick to the grain without it...couldn't hurt, might be a wicked improvement.

Good stuff all - thanks a tun. (Pun intended)

Just don't forget to vorlauf until clear.

 

[Jhoss]

A wedding present 23 years ago - a crystal 1.5 quart picture makes a wonderful jug. The wife is thrilled. I've only seen it used for gravy over the years. The visibility is cystal clear...another pun...I'll stop it now.