1 bbl HERMS - experiences

Systems, Gear, & DIY
1

Dear fellow brewers,

my name is Wolfgang and  I am a homebrewer from Germany. This is my first post in this forum and I registered here to get some first-hand experiences on brewing with a somewhat larger HERMS system.

HERMS systems are very rarely used by Germanys homebrewing community but I would like to build such a system as I fancy the automation possibilities. I already have suitable kettles to build a 1 bbl system - 25 gal as HLT, 40 gal as Mash tun and an old 45 gal Blichman Boilermaker as boiling kettle.

Currently, I’m investigating in supply sources within the EU to order the needed parts for the HERMS but as I do, I stumble over more basic questions regarding the operation of such a system. The german forums haven’t been of much help so I decided to register here and hopefully get some answers from your community.

I’m a bit concerned about the temperature rising speed during the mash. For a normal batch, some 30 gallons of wort have to be pumped through the HERMS coil and shall be heated up with 1°C per minute (approx. 1.8°F). Is the usual diameter of 1/2" for the hoses and HERMS coil big enough to get all that wort through the coil fast enough? Let’s say to rise the temperature by 20°F in 10 minutes, the wort needs to flow at 3 gals per minute to have all the wort passing the coil at least once. That’s pretty fast, isn’t it?

The one thing, most brewers in Germany discuss the most when it gets to HERMS, is the permanent negative pressure on the grain bed by pumping the wort through the coil. It is said that this will lead to closing the grain bed and stopping the flow almost completely and may even damage your false bottom. The faster the pump is sucking the wort out of the mash tun, the faster it will close up the grain bed. Did anybody of you HERMS brewers make this experience even once? Is this really an issue?

Actually, I’m looking for a suitable false bottom for my mash tun with 60 cm (23.6inch) diameter. Haven’t found any within the EU so I started looking for other options. One would be a domed false bottom with 15 to 20 inch diameter. The other would be a MattMill LauterHelix that I already use in my current (and much smaller) conventional setup. Is anyone using one of these in a HERMS system and can tell me the pros and cons about them?

Looking forward to reading all your helpful hints and tipps. Thanks in advance.

Kind regards
Wolfgang

2

Hi Wolfgang and welcome to the forum.  I think with the larger size of the batch at 1 BBL, you may have compaction issues and slow rise in temperature of the whole mash.  It seems that a larger diameter might become necessary to avoid the compaction and allow for enough flow to see reasonably acceptable step times.  I think either the false bottom or the stainless braid ( MattMill LauterHelix) you have will work in terms of getting clear recyclable wort, it is just a matter of avoiding the compaction by limiting the pressure differential.  If you can affix a sight glass as a manometer in the mash tun or better yet two manometers (one above the false bottom and one above), you can visually see that the runoff is equaling the return rate to the mash.

That is my short answer.  There is a link to a very good discussion on pressure differential in a post on this forum that I am sure someone will repost here.  It is worth a read.

Cheers (Prost!) and welcome, again!