Kaiser

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Your 100% conversion first wort gravity would have been around 1.073. You got only 1.060. This makes for a conversion efficiency of 60/73 = 82% which is a bit low. 18% of the starch didn't convert in the mash.

But your pre-boil numbers don't make sense. 7 gal @ 1.045 is 7*45 / (12.5 *36 pppg) = 70%. But you say that you got only 66%.

70% eff. into kettle and 82% conversion efficiency means that your lauter efficiency was about 85%. This is what I would expect from batch sparging 12 lb of grain twice.

So your problem is that your thin mash doesn't convert as well as your thick mash. I have been claiming that the opposite should be true. Odd how this didn't work for you. Was the recipe the same as the recipes that you mashed thick?

Kai

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JVD_X

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Kai - how is that calculated?

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Kaiser

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You'll have to use the plato scale, which is basically the weight % of the extract in the wort. And it works best when working with metric:

13 lb = 5.85 kg malt which has ~80% extract: 4.68 kg

He is using 22.75 qt = 21.5 l = 21.5 kg water

If all that extract is dissolved in all that water the wort strength in Plato will be:

100% * 4.68 / (4.68 + 21.5) = 21.1 %Plato

or 1.084 SG

Ooops, this doesn't really match up with my table and with what I said before. Let me run the numbers again and see if I have a bug in my table.

Kai

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JVD_X

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Yep - I got 1.082 in beersmith with 100% conversion.

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Kaiser

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Let's try again:

13 lb = 5.90 kg; at 80% extract potential this is 4.72 kg of extract

22.75 qt = 21.53 l = 21.53 kg water

So the weight percentage of the extract dissolved in that water is:

100% * 4.72 / (4.72 + 21.53) = 18.0 %Plato

This is 1.074 SG

My table is correct. JVD_X, if you do this with Beersmith you cannot use 22.75 qt as the resulting volume since the dissolved extract actually expands the volume of the water. That's why this calculation cannot be done as easily with the pppg based method. The expansion is about 0.075 gal/lb of dissolved extract. In this case 0.78 gal. This brings the total wort volume on the mash tun to 6.46 gal. With 36 pppg and 13 lb I get a gravity potential of 72 points.

No change necessary to my other posts.

Kai

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JVD_X

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But - the grain absorbs about 1.9 gallons of water or so (@ 0.15 gallons per pound) that reduces your water to 14.33 kilograms.

so 100% * 4.72 / (4.72 + 14.33) or 24.7 plato or 1.105

Again - I probably don't understand the science.

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Kaiser

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The "water" absorbed by the grain is actually wort and has the same gravity as the rest. Maybe some water that actually penetrates into the husks is just water, but that doesn't amount to 0.15 gal/lb.

Kai

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cactusgarrett

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I was just going by what Beersmith gave me for my Efficicency into Boiler based on the numbers i plugged in. I didn't hand calc anything.

What do you recommend i do in the future, then, if bumping to 1.75qt/lb didn't show an increase (taking into account loss of sparge efficicency)?

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Kaiser

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Quote:

Originally Posted by cactusgarrett I was just going by what Beersmith gave me for my Efficicency into Boiler based on the numbers i plugged in. I didn't hand calc anything.

Beersmith is right and I was wrong. I forgot to compensate for the expansion of the wort at boiling temps. It is 4% lager than at room temp and thus the efficiency appears 4% higher. 66% is correct and I also get this when I multiply the 7 gal with 0.96.



This brings us back to looking at the parameters in the mash and the most promising would be a finer crush, given that your pH is in an acceptable range. Do you have control over the crush?

Aside from that, do you check for iodine negative wort at the end of the mash? How long do you mash for and at what temp?


Kai

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slimer

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So Kai, I was trying to figure this out yesterday. If you have the Lintner of the malts in a mash, is there a formula that you can plug in to know how long you need to convert the starches?

This is the example I was trying to figure out. They are presented in percentage of the mash and degrees Lintner
40% of (Wheat Malt @ 74 deg Lint)
30% of (Vienna Malt @ 50 deg Lint)
20% of (15% Flaked Wheat & 5% Honey Malt @ 0 deg Lint)
10% Honey (Not in Mash)

My main fear is that if I do a 122 deg Protein Rest for 20 Mins and a 60 Min Sacc Rest at 150, the Vienna and the Wheat malts do not have enough diastic power to convert the Flaked Wheat and the Honey Malts.

This is at 1.5 qt/lb, but with my new system, I would probably be increasing the ratio.

I found this formula, but I don't know how it/if applies.