does over-milling effect mash conversion?

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does over-milling effect mash conversion?

Postby bredmakr » Wed Feb 05, 2003 3:16 am

I have been trying to increase my mash efficiency with little success. Can't seem to get over the 65% mark. I have hard water. So, I adjust the sparge water pH with acid. I use a 1.1 to 1.2 quarts water to 1 lb grain ratio. I do single infusion mashes for 60 minutes that hold great between 148 and 152F inside my 5 gallon cooler. I sparge with water at 160-170F. I recirculate until clear and my wort collection usually lasts between 30-45 minutes. I check a sample of the wort with iodine I got from my local pharmacy and it has never shown a reaction. I feel good about my mashing technique. The only two variables left are mash water pH and the milling. When I check the pH of the runnings it is usually below 6 so I'm not as concerned with this factor especially when brewing dark ales. So, the question is could it be the consistancy of my milled grains. I have noticed that as currently set the mill (Phil Mill) does a great job at crushing the grain while keeping a majority of the husks intact. Only one stuck mash thus far and that was with 8 lbs of pumpkin in the mash. (More on that later. Lathe I haven't forgotten about your request.) What I also notice is there is a noticeable amount of dust produced from the milling. Is my grain mill setting resulting in too fine a grist? Can this effect my mash efficiency?
Any and all input greatly appreciated.
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Some Observations & Hints....

Postby Mesa Maltworks » Wed Feb 05, 2003 1:04 pm

Regarding mash pH & conversion:

What is the pH of your mash once dough-in is completed? It should be between 5.5 and 5.2 with the optimum value being 5.3 for the best conversion.

"I use a 1.1 to 1.2 quarts water to 1 lb grain ratio"

Part of the conversion process is dependant upon hydrolysis. Therefore, if a grist is under-hydrated, your efficiency will be compromised. Presently, I feel you are not adding enough water to your grist to ensure proper hydration. I would raise the ratio to 1.33 qts water per pound of grist. Place around 25% of the grist into your mash tun and introduce a like amount of the dough-in water slowly and stir the mash until it has a smooth consistency like oatmeal and contains no balls of grain. Then introduce the next 25% and repeat the water inlet with stirring. Continue doing this until you are completely mashed in. Stir the entire grist until it has a uniform appearance. The begin your rest timing. This proceedure ensures that the grist is propery hydrated and maximum exposure to the water throught the mash will occur.

"I do single infusion mashes for 60 minutes that hold great between 148 and 152F inside my 5 gallon cooler" and "I sparge with water at 160-170F"

Your actual averaged mash temperature at saccrification rest end is probably more between 143 (if doughed in to 148) and 148 (if doughed in to 152). This is because the temperature at the top of the mash will be higher than at the bottom. The only way to get a true mash temperature reading is to stir the mash, then measure, which is a no-no ! This temperature is further lowered during vorlaufing which exposes the pre-wort to greatly lower ambient temperatures. This is where the sparge water temperature comes in....

You should always sparge at least at 165 degrees, but optimally 168 degrees. The overall intent of using sparge water is to separate the extract from the grain. The cooler the temperature of the mash, the higher it's running viscosity (thickness) will be. The higher the running viscosity, the more difficult a complete rinse becomes and, therefore, otherwise collectable extract is left behind in the tun. This is why it is essential to be on the higher side of your sparge temperature with the goal in mind being to raise the overall temperature of the mash to reduce the running viscosity and thereby allowing for a more complete rinse.

A note for those who can direct heat their mash tun or have additional infusion space:

A technique that ensures maximum conversion, enzymatic arrest and low viscosity is known as a mashout rest. Once the mash passes a conversion test via iodine, raise the mash temperature to 168 deg. F. and hold it there for 5~10 minutes. If doing so by direct heat, make sure to stir the mash as you are heating it to avoid hot spots which could introduce tannins to the pre-wort. This technique is highly recommended when using European lager and pils malts which tend to be less modified than other countrys products.

"Is my grain mill setting resulting in too fine a grist? Can this effect my mash efficiency?"

This is too hard to assess without physically seeing your crush. The optimal crush looks like starch chunks with largely intact husks and exhibiting little dust. An over-crush on one hand, exposes more starch surface area to be converted, but on the otherhand over-crushes the husks. The fine starch particles can lead to haze causing attributes to be set into the finished beer and can lead to a gummy mash that is hard to rinse. The over crushing of the husks will preclude setting a good filter bed. Both of these negatives can combine and lead to the dreaded stuck sparge ! So... a happy medium between the two is desired.

One way to better ensure an optimal grist is to "condition" it while milling. As the grain enters the hopper, lightly mist it with water. This technique helps restore some of the elasticity to the husks enabling the starch to be squeezed from the husk rather than torn from it. The husks also retain more of their original size and shape which lead to the setting of a better lauter bed and a subsequent increase in collected extract.

Eric
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Follow up

Postby jayhawk » Wed Feb 05, 2003 2:41 pm

Eric, can you please elaborate on this sentence:
"The only way to get a true mash temperature reading is to stir the mash, then measure, which is a no-no!"
A few threads ago we were debating whether or not to stir the mash, and I would like to hear your take on why stirring during the mash is not appropriate. In the half year I have been doing all grain, I have found that stirring the mash occasionally has increased my effeciency. However, increased effeciency could also be due to improved technique as I grow more comfortable with the all grain brewing process. An expert opinion would be appreciated.
Thanks
Chris
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mash tun capacity could be factor...

Postby bredmakr » Thu Feb 06, 2003 4:43 am

When making an ale with a target gravity of 1.058 or greater, which is usually the case, I have to lower the grist to water ratio so all the grain will fit into my 5 gallon mash tun. Based on your suggestions I need to increase the capacity of my mash tun to allow for a 1.33 ratio and improve my efficiency. This is excellent supporting evidence for the construction of a new mash tun and I just happened to be considering a number of mash tun options at this time. So, here is my follow up question. I am increasing my system capacity to make 10-11 gallons of wort. currently have 14 gallon boil kettle and I am trying to decide on a mash tun. If I want to make beers with O.G.s at or above 1.058 will a 10 gallon converted cylindrical cooler mash tun be sufficient? Based on my experience with the 5 gallon cooler and assuming it is a linear relationship, my intuition tells me NO. Perhaps I should be looking at a rectangular cooler with >40 qt capacity?

Thanks for the feedback Eric.
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Mash Stirring...

Postby Mesa Maltworks » Thu Feb 06, 2003 11:21 am

The don't stir recommendation only really applies to stirring after conversion is complete. This is to preclude hot side aeration, which has been said to have a number of detrimental effects on the resultant wort although I have not run trials to see how it would effect my brewing. I have encorportated this caution into my regimin after learning it at Siebel and reading ASBC (American Society for Brewing Chemists) and articles by respected brewing scientists and collegues over the years. This topic used to be a very hotly discussed item about 5 years ago, but seems to have died down.

The other possible bad effects stirring a completly converted and hydrated mash can come from the stirring action squashing the starch granules causing the release of compounds that can gum up the lauter screen or/and set a haze in the runnings that later will haze the finished beer. It is OK to periodically stir the mash while saccrifiying, but don't do it too often or you will cause temperature drops.

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Good assumptions !...

Postby Mesa Maltworks » Thu Feb 06, 2003 11:25 am

Yep, it's go to be bigger. The reason is that you will need the additional headspace for a sparge device (coil, Phil's sparger...) and for vorlaufing which causes some foaming. Try to buy/make a tun as large as you can accomidate... your next move might be a bigger kettle ! ;)

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vorlaufing?

Postby bredmakr » Thu Feb 06, 2003 11:44 am

please to be sharing definition of this term which is foreign to my meager brewing vocabulary oh great one.
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Vorlaufing Defined...

Postby Mesa Maltworks » Thu Feb 06, 2003 12:11 pm

Whoops ! Sorry... occasionally I let classical brewing terms slip into my posts forgetting that some may not be aware of them.

Vorlauf = to clarify in German. Vorlaufing is the process of recirculating pre-wort through the mash to set a filter bed which subsequently clarifies (vorlaufs!) the runnings.

This gives me a thought... once I finish the diatribe on cleaning and sanitization I promised to post in the article section, maybe I could post one on brewing terminology... would that be desirable ? At least that way if I slip into brewing terminology gobblety gook at least there will somewhere to refer to !

The sometimes unnecessarily too technical...

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Phil mill adjustment

Postby brakspears » Wed Apr 16, 2003 12:33 am

Sorry I know this is a bit late on for a reply, I was searching for mash tun info and found this thread, I have a Phil Mill which I noticed was crushing and tearing the grains, when I looked at the knurled roller the teeth were loaded with grain particles, I cleaned these away and the resulting crush is much better, the grains appear to be more punctured rather than torn, and the effort to turn the handle, mines powered by strongarm, is a lot less, hope this helps. Regards Nigel.
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