Mechanical pumps - bad for beer?

[SteveD]

In an article by a mico brewer, Ffos Y Ffin, in West Wales, printed in Brewer's Contact Dec 2006, the brewer talks about his pumping system which works on compressed gas alone by running the in-copper cooled wort from the boiler into a Kilderkin and then using compressed O2 to transfer it from there to the fermenter, oxygenating it to boot. The same method is used to move it from the fermenter to the conditioning vessel, except using CO2 this time.

One of the reasons he cites for using this method is so that the wort is 'never exposed to the turmoil of a mechanical pump' and refers to a report in the SIBA Journal, Summer '06 stating that the shearing forces caused by pumping reduce beer body.

I haven't yet been able to find this SIBA article online, and was wondering if anyone had heard of this effect or not, and what your opinions were of this notion.

Personally I haven't the knowledge or experience (brewed a lot of beer, but never used a pump) to be able to state with any conviction what the truth is. It is possible I suppose that the larger sugar molecules, dextrins, etc, which contribute to body in beer could be physically broken up by forceful pump impeller action. Dunno. There are a lot of pumps being used out there by brewers who somehow still manage to make great beer.

It could be that the author, Keith Thomas, is referring to commerical brewery setups where the pump might be more 'brutal' than say the little Totton pump that we might use.

[eskimobob]

One of the reasons he cites for using this method is so that the wort is 'never exposed to the turmoil of a mechanical pump' and refers to a report in the SIBA Journal, Summer '06 stating that the shearing forces caused by pumping reduce beer body.

My skeptic mode says that sounds like a load of old hogwash

[Seveneer]

My beers have improved substantially over the last year. I started using pumps in July. I wouldn't say that it's the pumps that have improved the quality of my beer but they certainly haven't damaged the beer in any way.

That said, I don't yet pump cooled beer.

/Phil.

[steve_flack]

It seems to be based on this article

http://www.scientificsocieties.org/jib/ ... 24-220.pdf

My (superficial) reading of it seems to be that the problems is greater at lower temperatures.

It's also mentioned here

http://brewingtechniques.com/library/ba ... epiro.html

There are a few possible disadvantages to RIMS, however. The biggest drawback is the relatively high cost of building the system. The cost can be quite high if you are mechanically challenged and therefore require prebuilt components. The nearly constant wort circulation yields a very clear wort, although that means the system must be well designed to avoid aeration of the mash liquor. The shear forces produced when pumping wort are also a concern to the RIMS brewer. Proteins (like enzymes) may be denatured more rapidly when subjected to shear forces. When shear forces are excessive, beta-glucans can form a gel that can inhibit filtration of the finished beer.

[Seveneer]

The way I read that quote (I haven't read the articles yet) it looks to me like a warning about hot side aeration escalating the denaturing of enzymes rather than aeration of beer at lower temperatures.

In my experience, HSA through recirculation can be avoided by ensuring that the return manifold is below the level of the mash and that the recirculation flow is well controlled.

Now I suppose I'd better read the articles linked by Steve (I haven't forgotten the pictures Steve, I just haven't get around to it).

/Phil.

[Frothy]

It could be said that if you are using pumps all the time there is a risk of dirt building up within them that could affect the beer flavour? They aren't easy to clean or sanitize.

Matt

[SteveD]

If he's using compressed gas driven pump it sounds like its a Flow Jet, these are pd diaphram pumps and much gentler on beer or wort than a cf impellar pump.

Daab, he's not using the gas to drive a pump, he's using gas pressure to directly move the beer, as you do when dispensing from a keg. He fills a kilderkin with wort or green beer then presumably caps it off and pressurises it with O2 for the former or CO2 for the latter, allowing the beer to flow from the keg to the fermenter or conditioning tank. In this way he avoids mechanical pumping of any sort.

What do you drive your flo-jet with? CO2 or an air compressor?

[SteveD]

It seems to be based on this article

http://www.scientificsocieties.org/jib/ ... 24-220.pdf

My (superficial) reading of it seems to be that the problems is greater at lower temperatures.

It's also mentioned here

http://brewingtechniques.com/library/ba ... epiro.html

There are a few possible disadvantages to RIMS, however. The biggest drawback is the relatively high cost of building the system. The cost can be quite high if you are mechanically challenged and therefore require prebuilt components. The nearly constant wort circulation yields a very clear wort, although that means the system must be well designed to avoid aeration of the mash liquor. The shear forces produced when pumping wort are also a concern to the RIMS brewer. Proteins (like enzymes) may be denatured more rapidly when subjected to shear forces. When shear forces are excessive, beta-glucans can form a gel that can inhibit filtration of the finished beer.

Yes, that looks to be along the same lines. On reading the 1st article the conclusion is that shear forces in hot wort can increase viscosity whereas at low temperatures in beer, it can reduce it.. I think.

What it doesn't do it is throw any light on wether the diddy pumps we are likely to use would have any tangible effect.

[steve_flack]

...it will run straight of my little 12v air compressor (for pumping up car tyres).

I was wondering if one of those would work.