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Gravity Reading question

I am about 3 batches into my transfer from extract to AG. The beer has tasted good, but my efficiency is not good. Right now I’m lucky to get 60%. I’m batch sparging and crushing my own grains with the Barley Crusher. I have a few things I need to look at as far as where the problem is (water quality, crush, etc), but I want to start at the beginning and that’s with taking my gravity readings. If I’m doing that wrong, then nothing else matters, or so I think.

Right now I use the refractometer our host sells. Brix/Specific Gravity Refractometer w/ATC. I take a gravity reading after the first run, then after the second run and then after combining both runnings in the boil pot. I then take a reading after the wort has cooled, before I aerate and pitch yeast. This is the reading I’m using to come up with my efficiency (using Beersmith).

Here come the questions…
-When I pull a sample of the cooled wort with the little dropper they give you, I’m pulling off the top. Does the wort settle out somewhat, which could cause me to be pulling a lower gravity portion of the wort?
-When I dump the cooled wort into my fermenting bucket, I pass it through a strainer. Would this mix it up better and give me a better sample?
-Does it sound like there is anything I could do differently in my procedure?

I want to make sure I’m sampling correctly before I start making other changes.

Any help would be appreciated.

Cheers!

Have you checked the refractometer against a hydrometer? And, can you post a grain bill + volume + SG reading?

It sounds like you’re pouring everything in the boil kettle through a strainer and into the fermenter. Is that right? If not (i.e., if you’re leaving some wort behind with trub), are you calculating efficiency using full post-boil volume or using the actual volume in the fermenter?

I haven’t checked the hydrometer. I’ve thought about doing it, just haven’t done it.

11lb 2-row
1lb crystal 40

4.9 gallon into fermentor at 1.050.

Yes, I’m pouring everything in, except the very last dregs of hops & wort.

Are those caught in a strainer or do you just stop pouring so prevent them from going in?

Also, what is your first runnings measurement?

Yes it is. I leave only a small amount in the kettle. Hops and some liquid. Not even 0.1 gallon I’d think.

1.062 first running at 3.2 gallon
1.030 second running at 3.2
1.047 preboil at about 6.4 gallon

I’d try to measure that to be sure. Just 1 quart (1/4 gallon) brings you from 55% to 58%. A quart doesn’t look like much in a trub-filled kettle.

Is that 3.2 gallons the total amount added before first runoff, or the total amount collected? Total amount added is more important for first runnings.

A lot is caught in the strainer, but I do quit pouring right at the end. Usually the strainer is clogged up if I have a recipe with 3oz of hops or more. I let most drain through, but quit pouring the very last in the kettle.

[quote=“ickyfoot”]
Is that 3.2 gallons the total amount added before first runoff, or the total amount collected? Total amount added is more important for first runnings.[/quote]

3.2 is the amount collected. I mashed with 3.75 gallon then added 1.25 gallon before I started the run off.

I’ll make sure to dump it all next batch. If I don’t have a sanitized spoon nearby the strainer is too clogged and I get lazy.

OK, that’s 20 quarts to 12 lbs, which is a thickness of 1.67. You should be getting somewhere around 1.074 for first runnings based on this chart
http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency#Determining_Conversion_Efficiency
. So you’re losing something during conversion, or your refractometer is measuring low.

Also, if your refractometer is accurate, your pre-boil efficiency is actually 68%. You’re either leaving more in the kettle than you think, or you have more than 4.9 gallons in the fermenter.

In terms of efficiency, it’s not important to make sure everything goes in the fermenter, but it is important that you know the full post-boil volume.

Wait, something’s definitely weird. Did you boil with the lid on or boil for a short period of time? With 6.4 gallons at 1.047, you’d have to have end up with ~6.0 gallons to get 1.050, which means you only boiled off about a 1/2 gallon. So, you either didn’t boil very long, kept the lid on, started with a lot more than 6.4, or ended up with more than 4.9. Or some combo of the above.

Once you have you have accurate measurements for volume and SG check your crush and your mash pH. Get those under control and you should be able to get your gravity close to 1.074 on the first runnings.

OK, that’s 20 quarts to 12 lbs, which is a thickness of 1.67. You should be getting somewhere around 1.074 for first runnings based on this chart
http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency#Determining_Conversion_Efficiency
. So you’re losing something during conversion, or your refractometer is measuring low.

Also, if your refractometer is accurate, your pre-boil efficiency is actually 68%. You’re either leaving more in the kettle than you think, or you have more than 4.9 gallons in the fermenter.

In terms of efficiency, it’s not important to make sure everything goes in the fermenter, but it is important that you know the full post-boil volume.[/quote]

It sounds like one of my problems is measuring volumes. I’ve been trying to be close, but not worried about being somewhat exact.

My runnings go into a fermenting bucket and I use the scales on the sides. My kettle has no measurement.

My head is starting to hurt!!

It was a 60 minute boil. The lid wasn’t on. What would the gravity be if I got down to 4.9 gallons if it couldn’t be 1.050 (and how to you calc that?).

(thanks for the continued help ickyfoot)

Ya, it sounds like I just need to write off that batch. Not dump it, just not worry about the math. I’m brewing again this weekend. I will pay much more attention to measuring. With extract, I never worried that much about it. I need to start forming better habits.

How do you measure what goes into the mash tun?

If 4.9 were the full post-boil volume, gravity would be around 1.062. So, either your pre-boil readings or volume measurements are low.

I use this calculator: http://www.brewersfriend.com/brewhouse-efficiency/

I’ve checked it against hand calculations and find it to be pretty accurate. If you want to get into the actual math, John Palmer lays some of it out: http://www.howtobrew.com/section2/chapter12-5.html. He lists average malt yields here: http://www.howtobrew.com/section2/chapter12-4-1.html

Just lessons for next time! I’m only just starting to get the process down. My first batches were in the low - mid 60s for efficiency, but still turned out good beer! :cheers:

[quote=“ickyfoot”]How do you measure what goes into the mash tun?

If 4.9 is the full post-volume, gravity would be around 1.062.

I use this calculator: http://www.brewersfriend.com/brewhouse-efficiency/

I’ve checked it against hand calculations and find it to be pretty accurate. If you want to get into the actual math, John Palmer lays some of it out: http://www.howtobrew.com/section2/chapter12-5.html. He lists average malt yields here: http://www.howtobrew.com/section2/chapter12-4-1.html

Just lessons for next time! I’m only just starting to get the process down. My first batches were in the low - mid 60s for efficiency, but still turned out good beer! :cheers: [/quote]

I was going to brew a wheat beer this weekend, but I think I’ll brew the same beer so I can compare my numbers. I’ll probably use different hops just to turn out something different, though.

I have a pitcher with measurements on it that I use to measure water going into the mash tun.

Could measuring the cooled and settled wort and pulling from the top give me a lower gravity reading? Does lower gravity wort settle out on top? If that’s the case, I could have had closer to 1062.

More specifically, the sugars settle to the bottom, but unless you waited awhile after pouring through the strainer, I can’t imagine you’d see a 12 point difference between the top and the bottom, but I suppose it’s possible.

Have you checked this against anything? If it holds a gallon, fill it up with water and see how much it weighs. If not, use it to fill something else up with a gallon of water and weigh that. Should be about 8.3 pounds/gallon (after subtracting the weight of the vessel).

Just FYI, getting the hang of this can be a mind bender, but it’s totally worth it!

More specifically, the sugars settle to the bottom, but unless you waited awhile after pouring through the strainer, I can’t imagine you’d see a 12 point difference between the top and the bottom, but I suppose it’s possible.

Have you checked this against anything? If it holds a gallon, fill it up with water and see how much it weighs. If not, use it to fill something else up with a gallon of water and weigh that. Should be about 8.3 pounds/gallon (after subtracting the weight of the vessel).

Just FYI, getting the hang of this can be a mind bender, but it’s totally worth it![/quote]

I pulled the sample when my my kettle was still in the ice bath and had been sitting there for 20 or 30 minutes. I didn’t get a sample after pouring through the strainer because of the amount of foam on top.

I’m going to figure out some more accurate measuring tools.

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