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For those that measure mash gravity

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nyakavt:
Do you find that a mashout is necessary to ensure 100% conversion?  I have been measuring mash gravity for the past 20 batches, but it has only been accurate for the last 7 or so since I started cooling samples in a sealed container.  I have thus far found that every beer but one required raising the mash temperature at the end (sort of a mashout, but it varies from 158-170F depending on how much water is in the tun) to ensure complete conversion.  After a 60 minute sacc rest I am several Plato low, I think 2-5 but I'd have to check my notes to be sure.

These results are confusing since I have heard a lot of people saying that a low adjunct mash is converted 'as soon as it hits the water'.  There may be some starches that are not gelatinized at the mash temperatures I am using, but I'd like some independent confirmation of this from other brewer's observations.

Some details:
Grist has been mostly Best Pils or Best Munich, with a 2-row and wheat base beer thrown in
Mill gap: .025" set by feeler gauges on the Barley Crusher
Grist is conditioned prior to milling with 1-2% water by mass
Mash temp has been 151-154 over the 7 beer span, losing 1-3° in the hour
Strike water volume is accurate to the nearest quart
Grist is measured on a scale accurate to the nearest 0.1 oz
Temperature is measured with the pro-accurate digital thermometer from NB, 32.0F in icy water and 213-214F at boiling (for wort).
Sample is gathered either into a 20 mL screw top test tube and immediately sealed, or in a 10 mL medical syringe. 
The test tube is cooled by submerging in a water bath, and the syringe is cooled by running cold water over the outside.  I tried submerging the syringe before but some water mixed with the sample and contaminated the reading.  Both methods agree exactly when taken on the same mash.
Sample size is typically 1-5 mL read on an ATC refractometer after cooling until it does not feel warm to the touch.
Grist potential OG is calculated from typical malt analysis sheets for base malts and values found in Home Brewing Wiki's Malts chart for each malt used.  Formula used: expected FW extract = 100 * grain laboratory extract / (R + grain laboratory extract) where R = water to grist ratio.

Kaiser:
I haven’t brewed with a single infusion in a while since I haven’t brewed a Pale Ale in a while but your experience matches mine. Even pale malts like Pils don’t fully convert in just 10-15 min. Those conversion time numbers, that you find on data sheets, are often misinterpreted. They should be used to compare malts and not to determine how long your mash will take.

For a long time now my standard mash incorporates a long (30-45 min) rest at 160 F which usually gives me full conversion after it is done. I have yet to take the time to plot the mash gravity over time.

Crush is expected to have a strong impact on how fast the mash actually converts.

Kai

kuphish:

--- Quote from: Kaiser on March 02, 2010, 09:30:46 AM ---For a long time now my standard mash incorporates a long (30-45 min) rest at 160 F which usually gives me full conversion after it is done. I have yet to take the time to plot the mash gravity over time.

--- End quote ---
Could you elaborate on your standard mash procedure, please?  I'm trying to maximize my conversion efficiency and right now I am stuck at around 92-93%.

Kaiser:

--- Quote from: kuphish on March 02, 2010, 09:37:20 AM ---
--- Quote from: Kaiser on March 02, 2010, 09:30:46 AM ---For a long time now my standard mash incorporates a long (30-45 min) rest at 160 F which usually gives me full conversion after it is done. I have yet to take the time to plot the mash gravity over time.

--- End quote ---
Could you elaborate on your standard mash procedure, please?  I'm trying to maximize my conversion efficiency and right now I am stuck at around 92-93%.

--- End quote ---

My standard mash, which I use for most of my German beers goes like this:

- 63 C (145-146 F) held for 30 – 45 min. This is the maltose rest and its length controls attenuation
- Then heating while stirring
- 70-72 C (158-162 F) held for 30-45 min (sometimes even 60 min). This is the dextrinization rest and it needs to be held until the mash is iodine negative. That may happen after as little as 15-20 min but I’m holding it longer since some literature sources mention head retention and mouthfeel improvements for an extended rest at this temp. The few explanations that I found involve glycoprotedies which are releases into the wort but the enzymes that would be able to degrade them have already been denatured. I haven’t done any experiments regarding this effect yet.
- Then heating and stirring to mash-out at 75-76 C (167 – 169 F)

My malt is milled at about 0.7-0.8 mm (28 – 31 mil). I think my good conversion is helped by the fact that I do stir the mash, mash thin and hold that long rest at 160 F. But mashing with direct heat may not be a viable option for everybody since it does take a little more effort.

Kai

kuphish:

--- Quote from: Kaiser on March 02, 2010, 09:49:17 AM ---
--- Quote from: kuphish on March 02, 2010, 09:37:20 AM ---
--- Quote from: Kaiser on March 02, 2010, 09:30:46 AM ---For a long time now my standard mash incorporates a long (30-45 min) rest at 160 F which usually gives me full conversion after it is done. I have yet to take the time to plot the mash gravity over time.

--- End quote ---
Could you elaborate on your standard mash procedure, please?  I'm trying to maximize my conversion efficiency and right now I am stuck at around 92-93%.

--- End quote ---

My standard mash, which I use for most of my German beers goes like this:

- 63 C (145-146 F) held for 30 – 45 min. This is the maltose rest and its length controls attenuation
- Then heating while stirring
- 70-72 C (158-162 F) held for 30-45 min (sometimes even 60 min). This is the dextrinization rest and it needs to be held until the mash is iodine negative. That may happen after as little as 15-20 min but I’m holding it longer since some literature sources mention head retention and mouthfeel improvements for an extended rest at this temp. The few explanations that I found involve glycoprotedies which are releases into the wort but the enzymes that would be able to degrade them have already been denatured. I haven’t done any experiments regarding this effect yet.
- Then heating and stirring to mash-out at 75-76 C (167 – 169 F)

My malt is milled at about 0.7-0.8 mm (28 – 31 mil). I think my good conversion is helped by the fact that I do stir the mash, mash thin and hold that long rest at 160 F. But mashing with direct heat may not be a viable option for everybody since it does take a little more effort.

Kai


--- End quote ---

Interesting, I think I'll give that a try on my next batch.  I know the problem isn't my crush, so it's probably the lack of agitation during the (single infusion) mash and having a second rest at 160F.  Two questions: (1) What is your conversion efficiency with this procedure?  (2) Do you use a different mash schedule for non-German beer styles?

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