CRAFT won the Pico system in a drawing in the year 2000. The system is used for demonstration brews, Big Brew and National Homebrew Day each May and November, at club parties, and is available for use by club members. This means that almost every brew has a different brewmaster, usually one who is not familiar with the Pico system, frequently one who is familiar with smaller (5 gallon) batches, and with brewmasters more familiar with extract and partial mash brewing than all-grain brewing. The point is that the experience with the Pico system varies all over the board. One major difference between what most of us brew with and the Pico system are the pumps. Most of us use gravity for our sparge, and because we mostly use our own systems we don't know how to control the flow with a pump. The mash tun in a Pico system is a half-barrel SS keg, uninsulated. Since we often brew outside, frequently in windy situations, our mash temp will stratify. The main point here is that the process we use with the Pico system is inconsistent. To brew good beer consistently you have to brew consistently. This is about improving our process with this system.
I'm still looking for data on Pico brews from the past. Please check your notes and brewing logs and send me what you have.
IMHO
At this time I believe that our actual conversion efficiency is easily 80+% based on having a high (1.024) lauter gravity when I stopped lautering for the baltic porter and the 70+% combined Brewing Efficiency that Allen and Jim had with their Belgium Tripple double brew. For this reason I suspect an issue with how we are lautering/sparging with the PICO system.
Also of note is the trend, admittedly with limited data, with higher gravities having lower System Brewing Efficiencies. (see chart at the bottom of the page)
The Great Experiment
80%
After talking with Brewers that have brewed with the Pico system (not ours) in the past Allen and Jim are brewing a batch of beer with a "modified" Pico system. The intent of the modifications are to lauter/sparge at a much slower rate and adding the ability to monitor that rate. The targeted rate is 1 quart every 1.5 minutes. This equates to a 10 GPH or .16 GPM lauter/sparge rate. This rate is in the middle of the range (.08-.3) that I found in my research and likely half the rate we have been typically using with the Pico system.
Jim and Allen brewed on Sat as planned. Here are their particulars:
Brown Ale Grain Bill---
Muntons Pale 2 row 21.75lb
Muntons 60L crystal 3.5lb
Munton roasted barley 1.75lb
Munton chocolate 0.5lb
Mashed in 9 gal water (above the screen) 1.33qt/lb
single infusion @ 153 F.
We filled the tun just to the bottom of the screen and pre heated it to
154F.
We had made an insulating blanket from that new aluminized bubble
wrap. after stabilizing the tun at 153-154F, we pumped mash water from
the liq tank (preheated to 167F) and added grain at the same time. with
27.5lb grain and 9 gal water the mash held 153 for the whole hour. we
checked for conversion at approx 40 min and got no color change, but
waited for the whole hr. Our water measured 6.8ph with total alkalinity
of 80. Mash Ph came out to 5.2 mash tun gravity at end of mash was 1.070
(measured 1.052 @ 150F) Carefully Lautered at .64qt/min adjusting as
necessary to maintain rate. We had trouble with the water pump losing
flow and had to constantly lower the sparge head to regain flow. this
resulted in periods where the top of grain bed became uncovered. We
lautered until we had 14.5 gal in the boil kettle. SG was 1.053-1.054.
Had to boil very slowly to avoid boil over .boiled for 1hr. Cooled and
transferred approx 12.5gal to carboys @ 1.055-1.056 Rest was left in
kettle with trub.
By my Calc eff was 80-81.5%
The Changes
(Previously) Changed the false bottom to allow more open area - the verdict is out on this one, definitely increased the open area in false bottom which should help prevent stuck mashes.
Made an Insulating Jacket for the Mash Tun - Typically the Mash temp would seem to hold and would then "crash" or fall rapidly.
Control Lauter Flow - This is the big one,
Control Pump Flow with a valve on the discharge of the pump.
Meter the lauter flow with a manual gage.
Measure the process very carefully - While this does nothing for efficiency it does allow us to know what was going on, Thanks to Allen and Jim
Note: While the low efficiency we observed was mostly due to having too high of a sparge flow others may not have the same issues.
Brewing Efficiency
The measure of how effective your brewing system is at converting the potential of the malted barley (grain) to sugar in the kettle or
the fermenter.
This is done by calculating the potential of your grain (calculated from weight and supplier specifications) and measuring the extraction from that grain by measuring volumes and gravity. Obviously accuracy is influenced by the accuracy of your measurements.
Brewing 101
Gravity Points
The reference for gravity points is pure sugar (sucrose) because it yields 100% of its weight as soluble extract when dissolved in water. Sugar (sucrose) contains 46 gravity points. That is one pound of sugar will yield a specific gravity of 1.046 when dissolved in 1 gallon of water. Put another way 46 points/pound/gallon (ppg). Ten pounds of sugar would contain total of 460 gravity points.
Maximum Yield
By reading a specification table (partial table for BRIESS 2-Row Brewers Malt below) we see the extract potential is 80.5% Extract Fine Grind, Dry Basis, 79.5% Extract Coarse Grind, Dry Basis. We will use the average, 80%, as the example. This means that this product has the potential (as measured in lab analysis) to produce 80% that of sugar (sucrose) or 80% of 46 ppg which is 37 ppg. This means that this one pound of this malt in one gal of water has the potential to produce a gravith of 1.037. This would be considered 100% Efficient. If we were to use 10 pounds of this malt we would have the potential of 370 gravity points.
In our example we will assume a simple brew with 22 pounds of BRIESS 2-Row Brewers Malt for 814 potential gravity points (37points per pound * 22 pounds)
We can measure our yield in too different places, either in the kettle or the frementer. If we account for our losses the results will be the same. The best place to measure the yield is in the kettle. What we want to measure is the total gravity points in the kettle. We do this by measuring the volume (hopefully accurately) in the kattle and the measured gravity. Lets assume we collect (sparge) 12 gallons of wort into the kettle at a SG of 1.050 for a total of 600 (50*12) gravity points. We subsequently boil this down to 10 gallons for an OG of 1.060 (600 points / 10 gal). This 600 ppg is our measured yield
Measured Efficiency
The measured efficiency is simply the measured yield (600) divided by the potential yield (814) or 600 / 814 = 73.7% Efficiency
Factors That Impact Efficiency
The Mash
The Crush
The crush or grind of the grain is a tradeoff between conversion and the ability to lauter the mash. The finer the grind, the closer to flour, the better the conversion but the harder to lauter. We need to be fine enough to convert, yet coarse enough to allow flow through the grain bed.
Conversion
When in doubt check for conversion, do this twice, the first time early in the process so you can see what a "failed to convert" looks like and when you suspect conversion is complete. If conversion is not complete we can expect a lower efficiency.
Lautering
The process of rinsing the sugars from the grain and into the kettle.
It is important to keep the fluid flow through the grainbed uniform and NOT compacted. How do you not compact a grain bed? By keeping it in a fluid state by keeping the water level above the grain bed and by not drawing off the wort too fast. It is believed that most problems with poor efficiency are caused by lautering too fast.
Lautering Rates
My estimate (guess) is that we have been taking no more than 45-50 minutes (frequently less) to lauter our 10gal Pico system. Assuming a collection of 13-14 gallons that is a flowrate of .26-.31 GPM or 15.6-18.6 GPH. This means that we are sparging at (or over) the fastest rate that I have found in the literature.
Research has indicated that many consider a rule of thumb of 1 quart per minute (.25 GPM) flow rate. This means with a 10 gallon brew, collecting 12 gallons of wort, that anything under 50 minutes is lautering too fast by any suggestion I have found. I have found references from 15 minutes (persumably for a 5 gallon batch) to 2.5 hours. Charlie Papazian, Among the most agressive I've found, says 20 - 30 minutes for an 8 lb grain bill. Assuming you are collecting 5-6 gallons that equates to a flow rate of 10-18 GPH or .17-. 3 GPM. My rule of thumb was 45-60 minutes for a 5 gallon batch (5-8 GPH or .08-.13 GPM). This gives a range of .08-.3 GPM
Note that especially the volumes used in these calculations are very rough (you may interpet that as guesses, estimates made after the fact)
From the BJCP Study guide
Lautering consists of draining the wort off the grain and sparging, or the addition of hot liquor (treated brewing water) to the top of the grain bed to rinse the sugars from the grain. This procedure should be done slowly, with the wort returned to the tun until the run-off is clear. This initial runoff and return of wort to the lauter tun is called a vorlauf and is critical to preventing astringency and haze in the finished beer. Lautering too fast will give poor yield, poor extraction rates, and possibly flush starch and protein fractions into the wort. Failing to re-circulate the initial runoff through the lauter tun until it is reasonably clear will have a similar effect.
