HELP! 2 hour knockouts -need advice fast!!

[omearabros]

We're a new small brewpub needing advice on how to speed up our knockout. Our last couple of brews had a 2 hour knockout which we believe has had a significant effect on the finished beer. Our kettle is double insulated and stays extremely hot, therefore simmering the wort the whole time. 2 hours of simmering does NOT seem like a good thing! Especially with late hop editions.

We have a 6 ton chiller with a 30 gallon reservoir (probably 45 gallons if you include 2" pipes to the brewery) plumbed directly to our large, single-stage heat exchanger (no pre-exchanger for city water.) I've got a ball valve on the glycol inlet and a butterfly valve on the hot wort inlet. We've been trying to throttle the two valves to end up at a constant temperature but can't seem to get it done. A few brewers have said to leave the glycol valve open at 100% and leave it, then throttle the beer accordingly. No matter what we do, it seems to fluctuate wildly until we slow everything way down to a crawl, leaving us with a 2 hour knockout. It didn't seem to me that a 6 ton chiller and 30 to 45 gallons of glycol would be undersized for 5bbl of wort, but I'm starting to think it is.

If we start out with the beer flowing slow it will come out in the 50's and 60's and we pretty much decimate the chiller and need to shut the knockout down to let it recover. If we start out with everything about 50% open, it's way too hot. What am I missing?

A few people have suggested a large cold liquor tank, but this is an immediate problem and we don't have time/cash to set up one up. I'm also considering just knocking the beer down to 100 degrees and then chilling it in our jacketed fermenters for a couple of hours before pitch, but that's not ideal. Also, our city water is warm, averaging 75 degrees, which seems too warm to knockout with?

Is there a trick to setting our flow rates?

We need to get this resolved ASAP. Thanks for the help!

Tim

[Thirsty_Monk]

Do you have two stage HX or single stage HX?

You should use city water on First stage and then glycol on second stage.

Is your HX properly sized?

[patbrewer]

Try switching to tap water. We have a 15bbl system and a 30bbl sized plate chiller and run 55° inlet water with knockout times at 30ish minuets. This lets us get our wort to 60° to 65° and capture heated water at 180°. Glycol is meant for a second stage of a chiller or to chill a cold liquor tank. If we ran glycol through the first stage of even our over sized chiller we would exhaust our chillers capacity quick. Also is your chiller sized appropriately? Try to keep your times over 30m and under 60m. These first few batches are the most interesting, good luck.

[omearabros]

Do you have two stage HX or single stage HX?

You should use city water on First stage and then glycol on second stage.

Is your HX properly sized?

Our HX is a single stage, but oversized for our system. It's probably for a 10-15bbl, and we're a 5bbl. Our city water is very warm, so I'm not sure it would knock down enough - though I haven't tried knocking out with it. It's probably 78 degrees.

[omearabros]

Try switching to tap water. We have a 15bbl system and a 30bbl sized plate chiller and run 55° inlet water with knockout times at 30ish minuets. This lets us get our wort to 60° to 65° and capture heated water at 180°. Glycol is meant for a second stage of a chiller or to chill a cold liquor tank. If we ran glycol through the first stage of even our over sized chiller we would exhaust our chillers capacity quick. Also is your chiller sized appropriately? Try to keep your times over 30m and under 60m. These first few batches are the most interesting, good luck.

Our HX is oversized - probably for double our size, but it's only single stage. Our city water is quite warm, 75 degrees right now, but I've never tried knocking out with it. Like I said, our wort is coming out of the kettle at 200F, so I figured 75 degree tap water wouldn't quite do it with a single stage... Am I wrong about that?

[patbrewer]

Do it and see; given you over sized heat exchanger you should be able to get your wort down to within 5° of your tap water temp. From there do as you said and crash in your FV to your desired pitch temp. Should be fine.

[Thirsty_Monk]

Our HX is a single stage, but oversized for our system. It's probably for a 10-15bbl, and we're a 5bbl. Our city water is very warm, so I'm not sure it would knock down enough - though I haven't tried knocking out with it. It's probably 78 degrees.

As ParBrewer said run your city water thru HX to HLT. If it is still too warm you can do three things.

1) finish cooling to desired pitching temp in the fermenter.

2) buy another single stage HX and plug it as a second stage. Run city water thru first one and Glycol thru the second one.

3) Get an oversized CLT and run it they HX.

You also could explore to get new two stage HX.

It should take you 30 min to chill your wort.

Good luck.

[TonyT]

One more for use city water. Remember you have a basically unlimited supply of water at 75F, but your glycol supply at 29F runs out after 30 gallons and after that you're relying on the chiller to keep up, which it sounds like it won't/can't.

[omearabros]

Thanks!

Thanks to all for your suggestions! Basically, this was a DUH moment for new brewers. We thought using our chiller to knockout would be the quickest method - and were we wrong! City water at 75F was more than enough to chill our wort down to just above pitch temp, without issue. The glycol chiller, though oversized for our brewery (in terms of supply to tanks) simply couldn't keep up and it made for a couple of snafu brews. Our heat exchanger is large for our system and allowed us to knockout in just 30 minutes, give or take.

Cheers! Thanks so much!

Tim

[Thirsty_Monk]

Glad it worked for you.
Good to hear.

[patbrewer]

Good deal, thanks for checking back.

[cpelz]

You may see added improvement if you mount your flow control valves downstream of the chiller. It will work more effectively flooded rather than starved...better contact.