Display posts from previous
Sort by

Thermometers.. I have no idea what my mash temp is

Post #1 made 14 years ago
by deebo
I thought I would do a little test with some thermometers to try and figure out if they are accurate or not.. now I really have no idea.
(So far I have been using the white thermometer to figure out my mash temp)

Cold (Ice and water)
Image


Mash-ish temp
Image


Boiling water in a cup
Image


Considering there was about a 3 degree difference between the highs and lows in almost every test I have no idea how I am supposed to get an accurate mash temp?
Last edited by deebo on 22 Jul 2011, 14:25, edited 5 times in total.

Post #2 made 14 years ago
by PistolPatch
I sympathise deebo!

Have a look at my post here where I compared 11 thermometers at varying temperatures. The conclusion there was...
...a 3 C variance at freezing, a 2 C variance at lager ferment, a 3 C difference at ale ferment, a 4 C variance at protein rest, a 5 C variance at mash temps, a 6 C variance at mash out temp and a 9 C difference at boiling point but...

...knowing the freezing/boiling variance of a single thermometer will not help you determine its variance at other temps.
LOL!

I think you either need to buy a certified thermometer (maybe they are accurate?) or take every opportunity to test your thermometer at mash temperatures against other thermometers. Once you have found a thermometer you are happy with, compare it to a non-digital thermometer you own and make a note of what the non-digital one reads (whether it be accurate or inaccurate) and use this as your mash calibration thermometer to check other thermometers against in the future. (Hope that makes sense).

I really see no other ways around this problem. There are heaps of dodgy thermos out there :angry:.

A good thread that can't be raised often enough.

:peace:
PP
Last edited by PistolPatch on 22 Jul 2011, 15:04, edited 5 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #3 made 14 years ago
by deebo
Tried some glass ones that seemed a little bit closer but still a difference between all 3
Image


I give up for now :P Will have to look up certified thermometers (though I hear they are very expensive)
Last edited by deebo on 22 Jul 2011, 18:29, edited 5 times in total.

Post #4 made 14 years ago
by Lylo
I picked up an older used Digisense unit on ebay for 30 bucks.It is very similar to yours that uses the 2 k-type probes.
It was used in a lab for years and works great.However it still needed calibration using the ice water/boiling water method.This point can and will drive you crazy if you let it.IMHO,Pick your favourite one and stick with it.
Also,turn off the decimals if you can,that is way to fine of a point.In no time you will be.Tense,worried and having a BMC. :argh:
Last edited by Lylo on 22 Jul 2011, 21:33, edited 1 time in total.
AWOL

Post #5 made 14 years ago
by PistolPatch
Lylo wrote:However it still needed calibration using the ice water/boiling water method.
Lyle, the freezing/boiling calibration method is another one of those brewing myths ;).

Download the spreadsheet in the link I gave above and you'll see just how much of a myth it is. I know there are several articles floating around, even in brewing magazines, saying you can calibrate thermometers this way. In reality, it doesn't work and unless you had a perfectly formed glass tube thermometer, there is no way this freezing/boiling calibration makes sense. All glass, for example, has imperfections - who knows where in the stem it is? See what I mean?

This point will drive you crazy but it's a great one to be aware of and not ignore. There are plenty of people out there mashing with thermometers 5 C out and these same thermometers may or may not read accurately at freezing and boiling.

There is no simple answer to this one no matter what the magazines say :evil:

:peace:
PP
Last edited by PistolPatch on 22 Jul 2011, 21:30, edited 5 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #6 made 14 years ago
by stux
Best answer is to probably pick the best of a bunch and reliably mash with that and then vary your mash temps until you get the results you want
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #7 made 14 years ago
by Lylo
I agree with all of that PP but,what is a simple homebreewer to do?I have already spent waaay to much time sweating this detail,when you consider the quality of beer being produce with cheap analog probe type therms (and worse), I think the ice/boiling combo should be close enough for most HB'ers.
It is, I think this type of fretting and nitpicking that keeps many people away from the homebrew process which we defend as simple and inexpensive.
Opps.Sorry this is starting to sound like a rant.That is not my intention. :nup:
AWOL

Post #8 made 14 years ago
by deebo
PistolPatch wrote:I sympathise deebo!

Have a look at my post here where I compared 11 thermometers at varying temperatures.
Thanks PP I did actually read this a while ago and it was the post that got me thinking about wether my thermometer was actually accurate or not.
Last edited by deebo on 22 Jul 2011, 22:09, edited 5 times in total.

Post #9 made 14 years ago
by PistolPatch
I don't think you are ranting Lyle :peace:

All-grain should be fairly easy. What I am saying is three things...

1. A lot of thermometers do not measure accurately at mash temperatures.
2. This is the one area of all-grain that there is no simple answer to (freezing/boiling calibration is not close enough - download my spreadsheet :)).
3. When first-time all-grainers get a problem, a dodgy thermometer is sometimes the cause.

I've written thousands of words on this issue (no exaggeration at all) and have made some suggestions as to how the problem can be reduced...

A. Compare your thermometer with other brewers any time you can. Any time you go to a brew day you should take your thermometers - it provides a rare opportunity.
B. When you buy one, at least get the one that reads the average - but that will only be at ambient. (As stux said above.)
C. As your first choice, buy the simple stainless, convex, brewer thermometers that I have pictured here previously as I have never found these to be more than a few degrees out.
D. Buy many thermometers.
E. Buy one that is certified.

Amongst my thousands of words, you will never see that I suggest calibrating your thermometer at freezing and boiling because it simply does not work.

So, yep, all-grain is easy but this is the one area where we should not pretend to have easy answers.

My rant is better than yours Lyle :lol:

:peace:
PP

P.S. deebo: sorry that there are no easy answers here :sad: .
Last edited by PistolPatch on 22 Jul 2011, 22:14, edited 5 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #10 made 14 years ago
by hashie
stux wrote:Best answer is to probably pick the best of a bunch and reliably mash with that and then vary your mash temps until you get the results you want
Hit the nail on the head Stux.

Use whatever thermometer you have and brew to it.

I mash at 64°C, according to my thermometer. The actual temperature could be anywhere from 60 - 68°C. But I know, for my tastes, the beer I produce is being mashed at the right temperature for me.

My message, don't rely on someone else (thermometer manufacturer) to tell you how to brew. Brew lots, record results and find what works for you.
Last edited by hashie on 23 Jul 2011, 05:38, edited 5 times in total.
"It's beer Jim, but not as we know it."

Post #11 made 14 years ago
by hashie
No worries Joshua, I'd use °F if I knew them or could be bothered with the conversion.

My post above was merely pointing out my tastes, which I believe would vary greatly to the general population. My point being, do what works for you.

Sorry for any confusion.
"It's beer Jim, but not as we know it."

Post #12 made 14 years ago
by Lylo
PP,I see that I am a rank amatuer of "The Rant".But you still don't hold a slim tapered flammable light source to SWMBO!
Last edited by Lylo on 25 Jul 2011, 20:44, edited 1 time in total.
AWOL

Post #13 made 14 years ago
by hashie
Lylo wrote:PP,I see that I am a rank amatuer of "The Rant".But you still don't hold a cancle to SWMBO!
Did you mean cankle :cry:
July 26, 2009 Urban Word of the Day
The area in affected female legs where the calf meets the foot in an abrupt, nontapering terminus; medical cause: adipose tissue surrounding the soleus tendon, probably congenital, worsened by weight gain and improved in appearance only by boots. From the English "calf" meaning wide portion of the lower leg, and "ankle" meaning slender joint of leg with foot.
Or maybe it was meant to be candle :headhit:
Last edited by hashie on 25 Jul 2011, 11:11, edited 5 times in total.
"It's beer Jim, but not as we know it."

Post #14 made 14 years ago
by PistolPatch
Lylo wrote:PP,I see that I am a rank amatuer of "The Rant".But you still don't hold a slim tapered flammable light source to SWMBO!
LOL Lylo!

My rant formula is as follows...

1. Spend all day on a jackhammer (I haven't had to do this for a few months)
2. Come home and refresh myself with a low alcohol beer or three whilst reading posts.
3. See a post with any one of the words/terms, 'thermometer', 'efficiency' or 'batch size'.

It's all downhill from there. By the sounds of your SWMBO, it's probably just like when you get home.

:lol:
PP
Last edited by PistolPatch on 26 Jul 2011, 23:31, edited 5 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #15 made 14 years ago
by Lylo
Ah she's ok actually.We were on a weekend vacation last weekend a long way from home, when I accidentally got lost in the hills around Vernon B.C. and stopped in at Hop Dawgs Homebrew Supplies for directions and came out with,a new kettle,another corny,20lb of specialty malts blahblahblah and $300cdn lighter.She just laughed.Happy pills are great!
AWOL

Post #16 made 13 years ago
by kartoffel
Sorry to revive an old one, but what are the thoughts about a thermometer that reads both extremes of calibration temperatures perfect within .1C every time. I got a new digital therm and every time I put it in mostly crushed ice and water it goes right to 0.0C and then when I try it in roaring boil water it reads exactly 100.0C even in F it reads 32.0 and then anywhere from 211.9-212.1. If it's reading these two extremes correctly could one be safe in the assumption that mash temp is probably very accurate? Other thermometers I have will read maybe one extreme ice or boiling spot on but not the other, and some wont read either correctly.

Post #17 made 13 years ago
by joshua
Kartoffel,

Your Thermometer is possibly very good.

Can you put under your Tongue to check you body temperature for a 3rd temperature point? It should read about 37C.

Two points make a line, so a 3rd point "Should" read correctly.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #18 made 13 years ago
by kartoffel
36.5C looks like I found a winner. I'll try to calibrate it on other known hot substances if the chance ever comes.
joshua wrote:Good Day Hashie, Forget about it, The U.S. is the ONLY place that still uses Fahrenheit.
So the do Cayman Islands and Belize apparently.
Last edited by kartoffel on 02 Oct 2012, 10:12, edited 6 times in total.

Post #19 made 13 years ago
by thughes
The most accurate way to check body temp with a thermometer is.......never mind, wouldn't want to use it for brewing after that calibration check. :nup:

---Todd
WWBBD?
    • SVA Brewer With Over 100 Brews From United States of America

Post #20 made 13 years ago
by Yeasty
kartoffel wrote: I got a new digital therm
Make, Model, where do you get one !!!

Mine's good, 0 in slush and 99.9 ish when boiling. But I don't care about the boiling.. I'm confident that its within .5 of a degree when mashing and thats good enough for me..

Finding a temperature source for mid range calibration is a PITA. I think the best you can do is x check with as many other thermometers as possible. Although with modern digital thermo's this is starting to becoming unnecessary.

I remember seeing somewhere a guy floating a blob of lard on top of a pot of water. When the lard started to melt he new the water was at the right temperature. For what and at what temperature I can't remember :idiot

Yeasty
Last edited by Yeasty on 02 Oct 2012, 15:43, edited 5 times in total.
Why is everyone talking about "Cheese"
    • SVA Brewer With Over 50 Brews From Great Britain

Post #21 made 13 years ago
by joshua
Yeasty, I Googled, I found "backfat: 30–40 °C", I left.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #22 made 13 years ago
by PistolPatch
Don't use thughe's calibration method :argh: :lol:
kartoffel wrote:If it's reading these two extremes correctly could one be safe in the assumption that mash temp is probably very accurate?
Unfortunately this is not a safe assumption. Have a look at the link in the second post of this thread and it will lead you to an experiment on 11 thermometers that shows this assumption may not be safe.

An easy to understand example of this would be in a glass thermometer where the glass stem may have slight thickenings or narrowings at certain points. For example the tube might be narrower between 20-40 C and then wider between 55-75 C. This would mean you'd get accurate measurements from 0-20 C and 75 -100 but nowhere in between. Digital thermometers have their own idiosyncracies as well.

I think the easiest way around this problem is to buy a few cheap thermometers of different brands and take a look at what they say at mash temps. Also when buying a thermometer, if several of the same brand are available, see if there is much variance between them at room temp. If there is, don't buy that brand.

I like the body temp as being a good extra calibration point :peace:.
Last edited by PistolPatch on 02 Oct 2012, 18:58, edited 5 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #25 made 13 years ago
by Yeasty
kartoffel wrote:The KM14 is the model of the thermometer I have. It looks like this. Seems to be accurate enough for me. If it can do ice body and boiling very accurately. I would think its pretty accurate at any temp seeing as it would be hard to fit a non linear curve to those 3 points.

http://img.directindustry.com/images_di" onclick="window.open(this.href);return false; ... 899713.jpg
Here is mine,Here
Last edited by Yeasty on 05 Oct 2012, 16:42, edited 5 times in total.
Why is everyone talking about "Cheese"
    • SVA Brewer With Over 50 Brews From Great Britain
Post Reply

Return to “Measurement, Mathematics and Records”

Brewers Online

Brewers browsing this forum: No members and 8 guests