My normal method is to dough in at 1:1 qt/lb and rest for 45 minutes, running a mash mixer for the duration. I then add some heat for 10 minutes to start the rise towards mash out. Then I underlet the mash to bring the ratio up to 1.2:1 and raise the temperature a little, with the mixer still on for about 10 minutes. I then recirculate for about 20 minutes (still with heat on) because that's how long it takes to get clear wort. Including dough in, total time is about 90-100 minutes.
Sparge takes 70 to 120 minutes depending on the recipe, using 170-174F water. I sparge to 2 Plato, but can go as low as 1.6 in some cases without astringency. Target mash pH is 5.3-5.4.
The goal of this new mash/lautering method is to extend out the higher gravity wort into the sparge and then stop before lower gravity wort is extracted (below 5 Plato or about 1.020). Those last runnings should still carry the final bit of sugar.
There's one paper out on the fermentability of wort under 8 Plato (1.035) and it shows that this isn't very fermentable.
A "perfect" sparge should look like this, where the top line is temperature of the runnings and the slope is the gravity.
More realistic is this slope of a fly sparge. The early slope up is recirculation as underletting is mixed in and heat is applied.
Batch sparging looks something like this:
To attain something closer to the "perfect" graph, more consistent heat and a longer slope are needed. Therefore, more water in the mash and less in the sparge become best practices. The concept of a 1:1 SPARGE is that an equal amount of water is used in both the mash and sparge.
AH-HA #1: It turns out that underletting or adding water to the first wort to thin the mash is counter productive. A mash ratio over 1.25:1 is also counter productive because an equal sparge tends to yield too much wort and too low a final gravity, though efficiency didn't seem to suffer. Best practice is going to be some kettle top-up water rather than sparging longer.
RECIPE METHOD: The water ratios are accurate, though not optimal. The DIPA simply can't take any more water and the IPA got a little too much. Between the two versions, I like the one that's a little drier, as it also hit my desired mash temperature of 152.
The mash mixer was turned off during the conversion rest and pre-recirculation heat up period. Of course it's off for recirculation and sparge. This allowed more air to stay in the mash bed.
RECIPE ANALYSIS: Conversion time was not affected.
DIPA 1st runnings: 25.7 Plato
IPA First runnings: 21.6 Plato
Both of these represent 100% conversion efficiency and beat the table on Kai's website. According to Kai, this is expected on a pro scale. We mill finer than most homebrewers.
Past practice says we expect 10 Plato runnings with the kettle about half full (10 barrels), then lose 1 Plato per barrel until full (20.5 barrels). There is a slope change at about 3 Plato where it slows to 0.7 Plato per barrel for about 3 barrels.
1:1 Sparge results: In this method we shut off sparge when the volume was very nearly equal to the mash volume. Ideal would be completely equal.
DIPA: 24.5 Plato at 9 barrels. 17 Plato at 13 barrels. 11 Plato at 16.5 barrels. 7.7 Plato at 18.5 barrels. Final runnings 5 Plato. Preboil volume 21.25 barrels (21.0 was the target). Preboil gravity 18.9 Plato. Net kettle efficiency gain of 10%, net yield gain of 6%.
IPA: 18.7 Plato at 10 barrels. 13 Plato at 12 barrels. 9 Plato at 14 barrels. Final runnings 3 Plato. Preboil volume 20.6. Preboil gravity 15 Plato. Kettle efficiency 95.5% where typical is ~93%. Net of 5% increase in yield.
Time and temperature both improved as well. The outflow temperature stayed steady at 164F throughout the sparge. Previously this has had a variance of up to 12 degrees F over the course of the sparge. First falling then rising near the end.
CONCLUSIONS: The tighter mash ratio and lower sparge volume seemed to net a greater increase in efficiency. I'll temper that with the fact that a pro brewer needs to be close to 90% efficient to maximize yield and profitability. However, my DIPA represents the least most efficient beer I make, so the added efficiency shows some real promise.
I'm going to stick to a 1.15:1 mash ratio and sparge with an equal amount of water. As of now, I don't think adding water to the mash would be ideal. However, it seems that a mash ratio nearer 1.5:1 works about as well as a tighter mash ratio.
I'm going to apply this method to lighter gravity beers that already have very high efficiency. The aim will be to improve flavor and fermentability. I plan to stop sparge at equal volume OR when gravity falls to 8 Plato, with the idea that final runnings will not be below 5 or 6 Plato but full extraction is attained.