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General Category => All Grain Brewing => Topic started by: abraxas on March 11, 2010, 02:17:26 PM

Title: Pressing the Mash
Post by: abraxas on March 11, 2010, 02:17:26 PM
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.

I know some commercial breweries press and then filter their mash between sparges http://www.alaskanbeer.com/our-brewery/sustainable-brewing/brewhouse-innovation.html

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.
Title: Re: Pressing the Mash
Post by: Kaiser on March 11, 2010, 02:30:47 PM
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.

Kai
Title: Re: Pressing the Mash
Post by: dean on March 11, 2010, 02:38:13 PM
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.
Title: Re: Pressing the Mash
Post by: Kaiser on March 11, 2010, 02:49:57 PM
Here is something else I found on their site that struck me as being a bit of BS:

Quote
CO2 recovery system

In 1998, Alaskan Brewing became the first craft brewery in the United States to install and operate a carbon dioxide (CO2) reclamation system. The system captures and cleans carbon dioxide, a natural byproduct of the brewing process, and uses it to package the beer and purge oxygen from holding tanks, saving money and the environment. This system prevents approximately 783,000 pounds of CO2, a greenhouse gas that contributes to global warming, from being released into the atmosphere each year. That is equivalent to preventing the emissions from using more than 40,000 gallons of gasoline annually.

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.

Kai

Title: Re: Pressing the Mash
Post by: Kaiser on March 11, 2010, 02:52:26 PM
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.

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.

Kai
Title: Re: Pressing the Mash
Post by: abraxas on March 11, 2010, 03:17:26 PM
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.
Title: Re: Pressing the Mash
Post by: hopfenundmalz on March 11, 2010, 03:47:14 PM
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. 

Title: Re: Pressing the Mash
Post by: Kaiser on March 11, 2010, 03:48:15 PM
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.

Kai
Title: Re: Pressing the Mash
Post by: Thirsty_Monk on March 11, 2010, 08:09:29 PM
Brewing Network just had a show with Alaskan Brewing Co. and they talk about mash press.
You can listen it here:
http://thebrewingnetwork.com/shows/611

audio file is here:
http://www.thebrewingnetwork.com/membersarchive/dwnldarchive03-07-10.mp3
Title: Re: Pressing the Mash
Post by: medicineman on March 12, 2010, 01:15:32 AM
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.
Title: Re: Pressing the Mash
Post by: Kaiser on March 12, 2010, 03:21:53 AM
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
Title: Re: Pressing the Mash
Post by: dean on March 12, 2010, 11:48:37 AM
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

Kai, have you been watching the history channel, I love watching scientist prove and disprove each other.... global warming.   ::)   :D  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.   :D   ;)

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.
Title: Re: Pressing the Mash
Post by: Kaiser on March 12, 2010, 02:14:37 PM
Kai, have you been watching the history channel, I love watching scientist prove and disprove each other.... global warming.   ::)

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.

Quote
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.

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.

Kai
Title: Re: Pressing the Mash
Post by: Kaiser on March 12, 2010, 02:16:06 PM
Kai, have you been watching the history channel, I love watching scientist prove and disprove each other.... global warming.   ::)

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.

I have similar comments to a past Zymurgy article about brewing green where some of the reduction of energy needed for brewing beer came from brewing less beer.

Quote
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.

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.

Kai
Title: Re: Pressing the Mash
Post by: dean on March 12, 2010, 02:34:14 PM


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.

Kai

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.
Title: Re: Pressing the Mash
Post by: howie on March 12, 2010, 02:35:01 PM
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.


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.

Sounds pretty awesome to me.
Title: Re: Pressing the Mash
Post by: dean on March 12, 2010, 02:43:25 PM
I can't see a homebrewer doing it but for a brewery... if it saves them money and they can re-use something, why not?   8)
Title: Re: Pressing the Mash
Post by: Kaiser on March 12, 2010, 03:53:45 PM
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.

Kai
Title: Re: Pressing the Mash
Post by: Kaiser on March 12, 2010, 04:01:32 PM
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.

Kai
Title: Re: Pressing the Mash
Post by: MrNate on March 12, 2010, 05:12:56 PM
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

Kai has a good point here.
Title: Re: Pressing the Mash
Post by: rabid_dingo on March 14, 2010, 04:58:47 AM
One question on the CO2 reclamation and purging tanks and what not....

Even if you manage to use the CO2 to pressurize the beer. Would it not be released into the atmosphere the moment
consumers open the beer at home? The idea that it would be pumped underground would be the only way that it would
actually be prevented from reaching the atmosphere. The idea that it was used in a later process in brewing only
re-allocates the release to a later time...No?  I would rather hear of breweries trying to calculate the amount of CO2 that
is consumed by plants and ensuring that that many plants were planted or growing on the property...

There are many many good ideas for the Green movement, but one has to take into consideration the actual footprint
of the idea before it can actually be considered green. Such as buying a used car is greener that buying a NEW hybrid.
Less impact to the environment if one keeps a car from going to a landfill as scraps from the metals that were harvested
prior to recycling the car as opposed to building a new car from all new material...

 
Title: Re: Pressing the Mash
Post by: BrewArk on March 14, 2010, 07:19:15 PM
The ONLY way to be sure the CO2 didn't seep out and make it's way to the atmosphere is to convert it into something else (carbohydrate & oxygen, or carbonate).

But that too would be difficult for a brewery.

As far as pressing the mash goes, I usually run out to the gravity I want, then put the rest into the compost.  The compost pile needs some water added from time to time anyway.
Title: Re: Pressing the Mash
Post by: brewboy on March 15, 2010, 03:42:34 AM
Quote
Such as buying a used car is greener that buying a NEW hybrid.Less impact to the environment if one keeps a car from going to a landfill as scraps from the metals that were harvestedprior to recycling the car as opposed to building a new car from all new material.

I know this isn't the right forum, but that is right on target and what I was saying (actually yelling) the entire time the "Cash for clunkers" program was going on. Building new cars, causes pollution. Fixing up old cars makes more sense in so many ways.

And to keep it beer related, old cars can carry grain, hops, and yeast just as well as new ones.  ;D
Title: Re: Pressing the Mash
Post by: abraxas on March 15, 2010, 04:02:04 AM

As far as pressing the mash goes, I usually run out to the gravity I want, then put the rest into the compost.  The compost pile needs some water added from time to time anyway.


I need to watch the water in my basement compost bin or I tend to get some mold.  The air exchange is limited to prevent it from drying out too much between additions...
Title: Re: Pressing the Mash
Post by: Kaiser on March 15, 2010, 12:27:10 PM
If you think about it, it could also be argued that Alaskan has a larger carbon footprint than most other brewers because the have to ship in all their raw materials (except water) and ship out most of their beer and their spent grain.

Kai
Title: Re: Pressing the Mash
Post by: MDixon on March 15, 2010, 12:27:49 PM
Kai - I'm pretty sure I saw a plate and frame filter at one of the breweries in American Beer. For some reason I am thinking it was Long Trail.

While searching to see if it was LT (I still think it was), I noticed Full Sail uses one:
http://www.wendmag.com/greenery/2009/06/sustainable-craft-brewing/

I suspect it is much like breweries brewing with biodiesel, many more do it than we know.
Title: Re: Pressing the Mash
Post by: daubon on March 24, 2010, 05:27:01 PM
On this topic I've pondered the idea of building a centrifuge to remove more liquid from the mash.  I figure that if this could be done one would need less sparge water and get better efficiency.  What do you guys think?  I may give this idea a try with our salad spinner to see what happens.

Thanks
Pepe
Title: Re: Pressing the Mash
Post by: Kaiser on March 24, 2010, 06:04:12 PM
That’s a nice article. Thanks for pointing us to it.

I think the industry is definitely moving into the right direction but something should not be overlooked: the bigger a brewery is the more efficient it can brew beer. This was touched upon in the article but let me explain this a little more. If you are able to brew beer 24/7 you can easily use the heat you reclaim during chilling of one batch to heat the strike or sparge water for a subsequent batch. You can even reuse heat coming off the boil kettle by condensing or compressing the steam. But this only works if you brew all the time. Most small breweries neither have the equipment to do that nor do they have the fermentation capacity to handle the large amount of wort that is produced. They also lack the capital to afford the more sophisticated systems necessary and as a result a lot of energy is wasted by not efficiently using the hot water from the wort chiller or the need to run with 8-10% evaporation in the kettle.

When it comes to energy and water use per unit of beer produced, home brew is arguably the worst due to the simple equipment and constraints we are working with. It starts with the use of R/O water continues with 10+% boil off using fairly inefficient heat transfer between burner and kettle and finishes with the use of an immersion chiller to cool the wort.

What offsets this inefficiency that many small brewers have is the fact that they raise awareness of the importance of going green. Over time that will become part of the natural thinking of people and together with increased prices of energy and waste disposal it should bring down our overall dependency on fossil fuels.

Kai

Title: Re: Pressing the Mash
Post by: dbeechum on March 24, 2010, 06:37:52 PM
If you are able to brew beer 24/7 you can easily use the heat

This was one of the two most impressive facts that I ran into when I toured the ABI plant in Van Nuys last year. Everywhere they can, they're capturing and redirecting heat. They take it from the chiller, the steam stacks, etc. Anything to save a few more joules and reduce water consumption.

The other was the fact that the brewing staff for the whole plant (which runs 24/7 and produces 250,000 barrels per month) was 6 folks per shift. 2 in the brewhouse, 2 in fermentation and 2 in packaging. Oh the electronic toys they have to make that happen.