@Oginme Enjoy your posts in this thread as well as many others. I decided to pre-order the 10.5 system after my initial research until I read through comments here. I already have a tun/boiler system so don't need this to brew but was looking for something to simplify my brew day.
Seems you are getting the best efficiencies from this system than most but I see you have the 6.5. Would like to duplicate (or try to) your excellent results.
Maybe you and others can populate "Best-Practices" for Foundry:
1) Might have missed it but what is your crush gap?
2) No sparge.
3) Low re-circulation - 1L/min or less.
4) Use a mash bag (probably doesn't affect eff.).
5) Block side wall perforations.
6) Add rice hulls.
Thanks
Mike
I will answer as best I can.
1) crush: I use a corona style mill, so there really is no set gap. I have a medium to fine crush with a minimum of flour. I measure my crush based upon the sampling of 100 grams of the grist. I spread it out on a cookie tray and collect any kernels which appear to be intact. I gently squeeze them to make sure they are whole and any which are shattered internally get put back with the rest of the grist. I then weigh the intact kernels to get a percentage of kernels which have not been crushed. I aim for < 1 gram (1%) which is usually made up of petite kernels. I then collect the rest of the crushed grain and what is left is indicative of my 'flour'. This is less than 0.1 grams for a normal grind.
When I first used my Anvil, I backed off a bit from my BIAB grind and was in the mid-70's for mash efficiency. My uncrushed kernels were around 2%, flour almost non-existant. After dialing in my recirculation rate and the impact of using a bag to line the mash basket, I started slowly tightening up on the grind. I eventually ended up at less than 1% intact kernels and 0.22 grams of flour with a mash efficiency at 88.2%. I noticed the level in the mash basket was starting to build up a bit following a 60 minute mash, so I backed off to the position I cited above. I am now consistently between 84% and 86% mash efficiency.
2) No Sparge: This is more of a personal choice. Using the settings I ended up at for crush, I have tried the Anvil recommended sparge and a more traditional split of infusion v. sparge water to achieve approximately equal run offs from each. The traditional split ended up a bit worse, but I also think that I was pouring the sparge water through the grains a bit too fast. The Anvil recommended sparge I tried twice and ended up at 85.3% and 85.9% mash efficiency. While these are at the high end of my data, it is not statistically significant enough to have me move from a no sparge mash, simply because it is easier for me and not enough of a difference to be chasing that little gain.
3) Low recirculation rate: I mistakenly started my first batch with a pretty strong recirculation. While I did not get a stuck mash, I could see channels when I pulled the basket out and the grain bed was pretty compacted. Maybe related, maybe not. Anyway, I figured that I started with 15 liters or so of water and if I recirculated at a rate of 1 liter per minute, the grains would see a change over in wort four times during a mash which is way more than I was getting when I did BIAB on my stove (no recirculation at all).
I dug deep into my Unit Ops texts because I remember doing modeling of liquor flow through a bed of wood chips for making pulp for papermaking. I rediscovered "Darcy's Law" relating to the flow of liquid through a porous media. Basically, the more of a pressure differential created between the top of the liquid column and the bottom, the greater the chance of compacting the media (grain bed). So if you pull wort from the bottom of the basket and deposit it on the top, you create that differential in pressure. The greater the flow you try to get through the media (grains) the greater the pressure differential from top to bottom and the more likely the grain bed will compact.
So I cut the flow rate back quite a bit to around the 1 liter per minute range and have held that ever since. In opening up the top of the Anvil at teh end of the mash and probing with my mash spoon, I feel no resistance from the top all the way to the bottom of the mash basket which is a good sign the grains are pretty loose and floating.
4) Using a mash bag: The mash bag does three things. First, it allowed me to crush a bit finer which gives me better efficiency. Second, it allows me to remove additional free water from the spent grains by hanging the bag and then squeezing to get as much volume out as is reasonable. My water retention in the grains is 0.434 liters/kg (0.415 fl oz/oz of grain). This gives me approximately an additional liter of wort recovered from my typical grain bill of 2.4 kgs of grain over just allowing gravity to pull the wort out. Thirdly, it makes clean up so much faster. It took me a good 15 to 20 minutes to clean out the mash basket without using the bag. It takes me about 6 minutes total to dump and clean the bag and wash the mash basket. No brainer for me.
5) blocking the side perforations: I had thought of this after looking at the Anvil and trying to decide which size to purchase. I do about 24 to 28 10-liter (2.6 gal) batches every year and usually only 1 20-liter batch. After talking to the Anvil reps at HomeBrewCon last year, I was pretty much convinced that I would be running the majority of my batches at the lower end of the system capabilities on the 10.5 gal model. I contemplated blocking off the side holes using SS shim stock, but decided that it was too much of a risk versus just centering on the model which fit the majority of my brewing habits. While I don't know for certain if blocking the side perforations might make the 10.5 gal model a bit more prone to stuck mashes, I would believe that someone could experiment their way to better efficiency with or without the side blocker for standard 5 gal batches.
6) Rice hulls: I added rice hulls twice, both times for wheat beers with 53% and 62% wheat malt in the grist. I had a bunch on hand I got from another brewer and figured that a small handful might help. The second time, I ended up at 300 grams of rice hulls for a grist of 2.2 kilograms of grain. Never had an issue with either one and will probably challenge that down a bit more on my next high wheat content brew.
I think that covers what you wanted to capture. If I think of anything else, I will edit and mark it as new learning/additions.