Mash temperature variation

[Dr Strange]

I have been absolutely smashing Biggie Juice clones. Ever since I bought a fermentation fridge.

I am struggling to.control the mash temperature on my rental **** cooker.

I get over shoots then pour in ice.

ideally you start low and increase in increments.

does it matter if higher temperatures are achieved too soon and then the mash dropsto earlier desired temperatures?

 

[yankinoz]

What temperatures?

If you raise to a mash out temp of 77 or higher, that pretty quickly breaks down the enzymes you need for starch conversion. If it happens to only part of the mash, you might have enough left for conversion if the grist has excess enzymes.

If your mash is in the low 70s for a short time, and you wanted lower, say, 65-67, no real harm is done, Spending time at the higher temps will favor conversion to less fermentable sugars. If, say, the mash is at 71 for 10 minutes, and you wanted 67, the beer will have a bit less alcohol and a bit more body than intended.

If your original aim was to do a step mash involving an acid rest (35-45), a protein rest (44-59), or both, and the mash is in the 60s or low 70s for any length of time, it's probably too late to go back down. Just go ahead with an infusion mash.

 

[JDW81]

There's a few things you can do to make things a bit more accurate:
1: Heat your strike water to a specific temperature (there's some calculators you can use which you plug your water volume, grain temp and weight et in to) prior to putting your grain in.
2: If you need to raise the temp, add boiling water from the kettle/another pot (again, there are some calculators around)
3: Ditch the crappy rental cook top and use an over the side element to raise your mash temp (I used one early in my brewing days and it worked a treat)
4: Invest in a temp controlled brewing system (obviously the most expensive option).

 

[Dr Strange]

Would this over shoot explain why the ferment has stalled at 10-19 not the 10-15 aiming for? It’s been stuck for 4 days despite inching the beer fridge up by 0.5C a day from 17.5c to 20C

 

[duncbrewer]

It could be, as less fermentable wort is produced from higher mash temperatures.
This article gives some info about the temperature effect on your grain conversion even if you aren't step mashing.

https://byo.com/article/the-science-of-step-mashing/

 

[Dr Strange]

Cheers

 

[MHB]

If you don’t have control over your mash temperatures you would be better off choosing a well modified Ale malt and doing an Iso-thermal mash (one temperature). Typically this is conducted at or close to 67oC, a little (a degree or two) hotter for fuller bodied beers and the same lower for dryer beers.

This temperature represents a good compromise between Beta Amylase that makes fermentable sugars and Alpha Amylase that produces dextrins (mostly).
You need to know your mass of malt, the mass of water (same as L, or close enough), the temperature of the malt and the temperature you want to mash in at. Plug that into the strike temperature equation (or a calculator) and it will tell you the temperature your water needs to be at so that when the strike water and malt are mixed together the whole mash wil be at the temperature you want.
It is important to be able to measure the temperature of the water accurately (the malt to) so a decent thermometer is required. Every brewer should have a good thermometer; I recommend a quality glass laboratory thermometer (less than $20), use this as your reference and check any other thermometers or sensors against it.
This is important; stir your strike water well before measuring the temperature!

Just a side point, there is a conventional way to report SG its in the format 1.019 not 10-19. SG is the mass of 1 unit of wort/beer/liquor... compared the mass of the same volume of water. So 1L of 1.019 beer would weigh 1.019kg.
It might not seem all that important but it can become so as you learn a bit more Brewmaths.
Mark

 

[Dr Strange]

Thank you