I have read online that pressing a mash is a bad idea because it can result in excessive tannin extraction from the grain. Has this held up? I have read a few conflicting opinions on this.
The downside to this seems like pressing the mash would result in messing up the natural filtration system that is the grain bed.
I am starting to think up a new rig, if I could press my mash I would think I would be able to design a two pot no-sparge rims system that would get decent enough efficiency.
Wow, I didn’t know any micro brewer in the US had a mash filter. Alaskan also states that they are the first and there is a reason for that. For one, those filters are more expensive than mash tuns and more complicated to maintain. From what I read, and it may only apply to older models, there is more tannin extraction with the pulverized grist that commonly used with these systems.
Though I think that it may be possible for a home brewer to build a system that presses the mash it will be more complicated and more trouble than a conventional lauter system. In a mash filter you have a very large filter membrane area which results in a very thin (few cm) grain bed. I doubt that you will be getting good results by pressing the grain bed against the false bottom of a conventional lauter system.
From what I could gather, the reason they do it is to save fuel/energy before they dry the spent grains prior to shipping them to farmers and ranchers. They also are the first or only microbrewer to capture Co2. Sounds like they are being very eco-friendly.
Here is something else I found on their site that struck me as being a bit of BS:
Either way the CO2 will get in the atmosphere. Brewing produces CO2 and unless they capture it and put it underground it will get in the atmosphere. And it is not such that the external CO2, which they may have been using before, was made just for making CO2. It was either the byproduct of some other process or captured from the air and bottled.
I do believe that we have to reduce our CO2 footprint but I disapprove of statements that make the layman believe that they are actually reducing the release of CO2 to the atmosphere. It is however a good idea for a brewery to reclaim their CO2 just from an economical point of view.
Yes the fact that the stabilize their grain before shipment made a compelling argument for a mash filter since the spent grain from those is already drier than convertional lauter tun spent grain. But that should not be reason why home brewers want to go that route.
As for the CO2, see my last post since I consider this a BS statement. What would reduce their carbon footprint is the use of a low evaporation boil system (Merlin for example) and/or extensive energy recycling in the brewery. Using the wort chiller to heat mash and sparge water, recapturing the heat from the steam coming off the boil and more.
I press my grain anyways since I move it to my basement compost system but I generally discard the liquid as I have assumed it is too high in tannins. I guess I will have to investigate this further next time.
I don’t know who was first, but Sierra Nevada also captures the CO2, removes the esters and alcohol that comes out as vapor, and uses the CO2 in the brewery.
The problem of pressing grains is not necessarily tannins but unconverted starches. The latter can be released from the grain and may not be converted by the time you heat the wort to a boil. That can be checked with an iodine test though.
The point is that they reclaim and use the CO2 produced from fermentation rather than using new CO2 for packaging. They do save CO2 by doing this. It all ends up in the atmosphere but they aren’t using as much.
The point I was trying to make is that even if you buy CO2 you are not adding any CO2 to the atmosphere since that CO2 has either been taken out of the atmosphere or is the byproduct of some other process (e.g. combustion) which was not allowed to go into the atmosphere yet. As I see it reclaiming CO2 in a brewery has only an economical benefit, but there is nothing wrong with that.
Kai, have you been watching the history channel, I love watching scientist prove and disprove each other… global warming. : They just did a show on N.America’s Ice Age, it was quite interesting. A friend of mine was also talking about how some people still want to tax farmers for cattle farts being a major contributor to global warming also… I guess dinosaurs and whatnot didn’t fart, they were ladies.
Maybe a change in the topic, I don’t know but has anyone tried brewing with snow? The same friend I was talking about mentioned to me that snow has nitrogen in it… I suppose it would probably escape during the boil though? I was thinking yeast need the FAN.
Don’t get me wrong. I believe that global warming is fact and that we are mostly to blame for it. I just don’t like it when prople jump on the band wagon of “carbon foot print reduction” when they are not actually reducing the carbon footprint. I leave it at that since this is not the pub.
Brewing with snow is the same as brewing with rain water. Though it is very soft water it also contains all the pollutants you find in the air and as a result is gererally considered unsuiatble for brewing. It also takes quite a bit of energy to melt the snow.
I don’t doubt what you’re saying but my friend knows quite a bit also being a farmer, according to him nitrogen is picked up in the stratosphere or one of the atmospheric layers at lower temperatures and stays with the snowflakes compared to the warmer temperatures of rain water. ??? He says snow reduces the amount of nitrogen needed for fertilizer, winters having heavy snows produce a more nitrogen rich soil saving him money.
In the Brewing Network discussion, they do mention that it was expensive, but they are saving something like 400,000lbs of grain a year and a million gallons of water per year as a result of the increased efficiency of this machine. I’m guessing it would pay for itself VERY quickly with those kind of savings.
As others have said, they did it primarily to save in the cost and hassle of drying their grains after brewing. They don’t have anywhere locally to dispose of them, so they have to ship them off of the island.
Finally, they did address the tannin extraction/flavor issue. They basically said they did extensive testing with a demo model of the machine, and no one could tell any difference in the finished beer.
Despite their good efficiency, mash filters have not caught on in the industry. It may have to do with the increased tannin and lipid extraction that worries some brewers even if they may not be able to tell the difference. From what I read a modern mash filter can gain your about 1-2 % over a state of the art lauter tun. Using the 2% number I estimate that Alaskan uses about 20 million pounds of grain per year. If it takes about 10 lb to per gallon of their average beer that equates to an output of about 66,000 bbl per year which seems about right.
Back to the carbon thing. Given the current focus on carbon trading it seems that breweries might be able to generate some additional income by capturing and storing the excess CO2 from the brewing process. If they find an effective way to sequester it somewhere where it is not released into the atmosphere they can start selling carbon offsets. Might not be worthwhile for most micros, but the big boys create enough CO2 for this to be a worthwhile exploration.
They just did a show on N.America’s Ice Age, it was quite interesting. 
A friend of mine was also talking about how some people still want to tax farmers for cattle farts being a major contributor to global warming also… I guess dinosaurs and whatnot didn’t fart, they were ladies.