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Old 11-10-2009, 01:13 AM   #1
Chef Stress
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Default missed SG by 8 points - 56% efficiency - ugh

So I brewed a Rye today and I had some serious temp. and gravity issues. I figured they're related, but I wanted to see if anyone had any advice.

Recently purchased two Blichman Brewmometers fromm Northernbrewer.com, one for the kettle, one for the MLT (a cooler). I calibrated them in the AM in a glass of warm tap water using a digital thermometer (my infant sons).

I hit 164F in the kettle, and transfered a lil over 5 gallons of the hot water to the MLT. At that point the Brewmometer on the MLT read about 145F. I double checked the water temp in each vessel using an instant read meat thermometer. Neither reading matched the Brewmometers. At this point I knew I was effed, so I decided to go ahead and trust the temp readinng o the kettle and doughed in my grist. After 5 minutes, I checked the temp, and decided to add hot water (which was now supposedly at about 180F) 'cause I had decided that I was getting a closer to accurate match with the instant read annd the MLT reading than I was gettinng with the innstant read ant the kettle. I ended up adding enough 180F+ water to get a reading of about 150F in the MLT, after about 15 minutes at around 135 or so. I let that rest for about 30 minutes, and then decided that I would go to the parmacy on the corner and get a bottle of iodine to do a starch test. I did the starch test, and the iodine stayed redish-brown. I did another test, and got similar resullts. So I volarufed (x2) and drained 5 gallons. I then added about 3.5 gallons of 180F+ sparge water to the MLT (to get a total of about 8 gallons) and then started my boil.

When I hit boil, the temp reading on my kettle was pinned against 120F, so I was at least 18F off on all my kettle readings for my mash.

I missed my target pre-boil gravity by 8 points (1.040), and my SG by 8 points too (1.048).

So I guess I have 3 questions:

1) What the eff is up with my thermometers? Anyone have similar problems ever? Is there a specific temp I should be calibrating at in order to get accurate readings?

2) Did I miss my traget gravity because my temps were off? What else if anything could be wrong with this batch?

3) This is sort of an aside, but was doing the Iodine test the right thing to do? I figured cause I got a readinng that I had fully converted Icould go ahead and drain my MLT. If I had waited lonnger might I have gotten better efficiency? I calculated that I got about 56%.

Thanks for any help. This is my 6th AG batch, thermometers have been an issue every time. Though I haven't missed gravity this bad, and my previous batch I hit my gravity dead on.

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Old 11-10-2009, 01:46 AM   #2
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I have done about 10 all grain batches myself. And have experienced some similar gravity readings. To compensate I always keep some malt extract on hand for brew days. I am a bit confused in your description of all the different temps but I am pretty sure if you can hold your mash temp over 145 for an hour you will get complete conversion. I would guess that your lack of efficiency was due to a process, coarse grain crush, not enough stirring or poor sparging.
Like yourself, my efficiencies have varied a lot. I think my crush is very inconsistent which leads to poor efficiency. I have a crappy corona type mill that is hard to keep a consistent gap setting. (Thus my next big purchase will be a barley crusher).
As for thermometer calibration I have always done them using ice water to hit 32F.
One other question for you, do you preheat your mash tun? If you do not, when you dough in, you will lose heat.
Anyway make sure to keep some extract on hand, "mostly grain" tastes nearly as good as "all grain" to me.

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Old 11-10-2009, 05:07 PM   #3
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I remember another post somewhere on the site detailing where someone had huge lag time and poor temp accuracy with the Blichman thermometers that had a angling readout. They were accurate when the dial was straight and wouldn't move when the dial was angled, not sure if this is your problem but it might be applicable.

Will

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Old 11-10-2009, 05:17 PM   #4
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Poop on analog thermometers, I don't care what anyone else says. There are far more accurate digital ones for way cheaper.


Quote:
Originally Posted by Chef Stress View Post
When I hit boil, the temp reading on my kettle was pinned against 120F, so I was at least 18F off on all my kettle readings for my mash.
???????????????????, that makes zero sense.
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Old 11-10-2009, 05:36 PM   #5
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Quote:
Originally Posted by wildwest450 View Post
Poop on analog thermometers, I don't care what anyone else says. There are far more accurate digital ones for way cheaper.
Hijack!

Like what brand? I'm in the market.
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Old 11-10-2009, 05:46 PM   #6
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If you are, then be diligent about temp and make sure your stir like crazy to get the grains/water mixed well. It helps to make sure that your MLT is preheated. Strike temp does not take into account the heat loss from your mlt.

It doesnt sound like you mashed for 60 min. I'm not saying it wasn't done converting, just saying that if this is new to you, you might want to do it for atleast 60 until you fine tune your system. Posting you recipe might also help to make sure all the gravity points are there.

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Old 11-10-2009, 07:07 PM   #7
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Quote:
Originally Posted by jmo88 View Post
Hijack!

Like what brand? I'm in the market.
I use this one for mash temps
http://www.williamsbrewing.com/SELF-CALIBRATING_DIGITAL_P1434C102.cfm

And a cheap remote probe thermometer from wal-mart(checked with above therm, very accurate) for strike water, it has an alarm. Just don't fully submerge the probe.
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Old 11-12-2009, 01:56 AM   #8
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Doh - I meant 8F off from boiling (at least),

and yes, I did forget to preheat MLT, I was in a hurry and forgot,

recipe is:

Ingredient Amount % MCU When
US 2-Row Malt 7lb 8oz 45.5 % 2.1 In Mash/Steeped
US Rye Malt 7lb 0oz 42.4 % 4.0 In Mash/Steeped
US Rice Hulls 1lb 0oz 6.1 % 0.0 In Mash/Steeped
US Flaked Barley 8.00 oz 3.0 % 0.1 In Mash/Steeped
German Roasted Rye 8.00 oz 3.0 % 18.8 In Mash/Steeped

I'm going to try and recalibrate the two Blichman's with boiling water for my next brew. They're a headache though.

Took Gravity reading tonight (after vigorous fermentation) and I hit 1.010 so I'm not so worried, really just pissed that I paid so much for the thermometers and I feel like they were a waste.

Thanks for all the feedback/ advice,

Stress

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