View Full Version : Is this possible?

12-07-2003, 03:30 PM
A question: is it possible to perform a partial volume brew on commercial craft brewing equipment. For example, if I buy a complete brewery sized around a 10bbl brewkettle, can I sucessfully/practically make a 5 or 7 bbl batch on this? I'm thinking about 'turndown' during initial startup and early operation, and/or quiet periods (I live in a seasonal tourist area).

Any advice - or indeed actual experience (has anyone given it a go?) - would be appreciated.


12-07-2003, 03:53 PM
I've brewed 10 barrel batches in a normally 15 barrel system. I'd imagine there's a lower limit to how much mash you can comfortably sparge in a given mash tun (you don't want the grain bed TOO shallow...). Another thing to be concerned with is having enough liquid to cover your steam panels (if you have a steam kettle) so you get full use of your heating (and don't burn anything!).

Cheers, Tim

Mike Hall
12-07-2003, 08:05 PM
Don't forget about your whirlpool in the boil kettle if you have one. Your level after boil should be just above the whirlpool outlet hole in the kettle. I brew on a 25BBl system and have brewed 11 bbl batches on the same system.

dick murton
12-08-2003, 06:10 AM
I have not brewed small lengths with micro systems, only with bigger systems (400hls + nominal) but in this particular system found that we had to raise the mash temperature slightly. From memory, when brewing a 120 hl brew in a 400 hl system, we had to raise the mash in temperature by 1 to 1.5 deg C to compensate for the extra relative heat absorbtion by the mash vessel (mash tun - no heating or mixing). Otherwise our final gravities were a degree or so low, with high alcohols and thin tasting beer.

The only problem we had was that some fermenters cooling jackets and or temperature probes were too high, sitting above or partially above the wort level.

Pro rata yeast pitching volumes etc and you shouldn't have many problems.


12-08-2003, 11:03 AM
We did this all the time at my last job. We had a 10 BBL system and regularly brewed 7BBL batches. The key for us was that we expected to do this from the beginning and were able to assure that the equipment we bought was able to accomplish this task. The keys for us, which reiterate some of the other comments posted, were threefold. First, you needed a mash tun that might be slightly taller (and less wide) than average for a given size system. This is a problem when brewing high gravity beers at the full batch size, but necesary to ensure proper lautering at the smaller batch size. Second, you may want to have your whirlpool inlet positioned slightly lower than normal in the kettle/ whirlpool tank. Third, you want to ensure that the cooling jackets and temperature probe are positioned below the level of the smaller batch size. If your fermenters have a cooling jacket that is completely above the liquid level, you may want to install a valve on the inlet of that jacket so that you can close it when you are fermenting a smaller batch.

Generally the batches scaled up fairly easily but we found that we generally got a little better hop utilization on the larger batches.

12-08-2003, 06:34 PM
I agree with the above comments... It's definately doable, there's just a lot of little issues to consider. With an undersized mash tun, the only way I can brew big beers is to short fill the kettle. We run a direct fire kettle, and run into more issues with scorching, hop utilization, evaporation etc... Nothing that trial and error won't solve. That being said, I still always prefer to brew a whole batch whenever possible. On our brew size (7Bbl), labor is on of the biggest costs... so why not brew the extra few barrels while you're at it?

12-08-2003, 09:49 PM
Appreciate all your excellent replies...:)

12-11-2003, 05:16 AM
Another issue to consider is cleaning your fermenters after a small batch. On a 10-15 BBl tank this shouldn't be a problem as it is easy enough to manualy scrub and reach everywhere. In my case I often ferment 15Bbl batches in 30 Bbl fermenters and when its time to CIP I noticed that I need to use more detergent and more hot water because the sprayballs on most tanks concentrate on the top quarter of the tank where your Krausen ring would be if you did a full batch, but on half batches the krausen ring is halfway to 3/4's down the tank and it doesn't get hit as well. Sometimes I have had to manually scrub which is a pain in the butt on bigger tanks, or I have run an Acid wash then an Alkaline. Using more alkaline with more hot water than usual seems to work as long as the beer hasn't been in the tank for several months. Just my 2 cents.

dick murton
12-11-2003, 07:41 AM
Re the comment about problems cleaning. This suggests to me that your sprayball is undersized and/or under pressured so is not wetting thoroughly, large amounts of the caustic falling directly to the bottom, not the vessel walls. Sprayballs are not really designed for high impact cleaning action, but by wetting with a certain amount of scouring action, particularly on the side walls.

If using say 1.5% v/v formulated hot caustic (50 deg C), 10 minutes recirc should remove virtually all the hop / yeast / trub ring irrespective of fill height. Another 10 minutes after that should normally be more than enough, after all electrical energy for pumps is expensive.


12-11-2003, 08:16 AM
I believe the effect I am experiencing is not due to sprayball or pump defficiencies as I have visually verified that my sprayball is working correctly. What it comes down to is that at a given amount of detergent I can successfully clean the tank for any given batch size. For a 30 Bbl batch in a #30 BBl tank I can specificaly use 8 gallons of 150 F water with 3/4's oz PBW per gallon, but for a 15 BBl Batch in a 30 Bbl. tank I need 12 gallons at 1 OZ per gallon. So it is an issue of practicality for my particular situation. If you can use less chemical and still be effective, do it, its cheaper. Just realize that changing batch size can effect chemical usage. Surely the stronger solution will clean the large batch effectively but not the other way around. Im sure most would agree that if the sprayball is directly spraying an area with detergent it is more effective than if it is merely washing over an area ie. the area under the manway that gets washed with a very weak flow of detergent and usually requires a slight scrubbing manualy. Im not disagreeing merely clarifying. In my experience many small scale brewers over use chemicals when experimentation can signifigantly cut down on chemicals without sacrificing effectiveness.

dick murton
12-11-2003, 10:26 AM
If my calculations are anything like correct (I am not sure of the exact translation as I am not used to US gallons etc, and haven't used the units translation file available) then I reckon you are using approx 0.75% caustic. Good on you for keeping the strength down. I assume BPW is caustic based. Possibly the additional loss of detergency is due to the extra volume of CO2 in the vessel at the end of fermentation. If sodium carbonate is a lousy detergent, sodium bicarbonate is even worse !!

If you are really struggling with yeast etc tidemarks , you could always try a little hypochlorite mixed in with the caustic, PROVIDING the pH is high, greater than 11 is the normally quoted figure, to stop the chlorine in the hypo attacking stainless.

Agree with using periodic acid wash, especially if you are in a hard water area, but would be tempted to do it after the caustic clean, purely as scale remover.

Nothing like getting off the original topic is there !!!

12-11-2003, 07:00 PM
Make the bigger batch and keg up the difference.