Hello all! I'm going to do a complete teardown of my Mega II and descale/clean it all up. I can't find much information regarding the water when using citric acid. I realize being "hot" will work better, but can one do a room temp descale with citric acid? If so, how does this affect the citric acid to water ratio and how does this affect the soak time. If not, what quantifies "hot"?

Thanks in advance!

Roughly, the speed of a chemical reaction doubles with every 10°C rise in temperature.

Assumimg a boiler temperature of 110°C, then a room temperature reaction will be 1/(2^((110-20)/10)) or about 500 times as long.

Uh, that's a long time.

What about a higher concentration? My fear here is that at a colder temp might not dissolve a higher ratio of citric acid to water. Any recommendations on this? It's my understanding 1-2 tablespoons in 1qt. of water is what's recommended if doing this with the machine at temp.

Put your parts in a bucket, get out your largest stainless steel stock pot. Fill it with water, bring it to a boil. Add you citric acid powder and pour it into the bucket with the parts and repeat until everything is under water. If it is not boiling, it is not hot although anything is better than room temperature. Just a matter of wanting to wait 3 hours or 3 weeks.

I basically used the process that Dave just described. I ended up needing about 24 quarts per descaling batch to soak the boiler of my Elektra (in a plastic orange 5 gallon Home Depot paint bucket), so I would boil each 8 quart batch of water, dissolve the citric acid, let the rolling boil roll the solution around, and pour the water into the bucket. I used about one heaping tablespoon of citric acid per quart. While I didn't have the luxury of a 5 gallon enameled pot to keep the boil going constantly while soaking (as Phillip recommended in my rebuild thread), heating the water and leaving the boiler soaking overnight in the bucket worked for me.

Thanks for the replies.

I feel a little silly now b/c I have numerous stainless containers from my brewing equipment; not sure why that hadn't crossed my mind. I think I'll do two 10gal pots on the stove (one for the boiler, one for the rest) or do everything in a 15gal pot on my propane burner. I'm leaning towards two pots on the stove as to keep it in doors (supposed to be cold and wet this weekend). Even if it doesn't stay at a boil, it should still be fairly warm.

In a boiling pot, is two hours a reasonable time frame? The scale isn't too bad, I just want to start fresh with the machine.

When I cleaned out my heavily scaled Elektra T1, I placed it in a bucket with hot tap water, dumped a lot of citric acid in there (1 tablespoon per liter) and left it outside for about three weeks (I was in no hurry). A few times I reached in and cleaned out the heavy scale with my garden hose, then just put it back in the bucket. The copper tubing was in there as well. I didn't change the water.

-phillip (not the same one as mentioned above)

Just an update, boiled the tubing and heating element with a 1tbsp citric acid to 1quart of water ratio. Everything was bright and shiny after 2-1/2 to 3hours. The boiler I did separately; after about 4 hours it still has a ways to go. Because of the size, I can only submerge 1/2 the boiler at a time so I've got a ways to go with that. Don't know why I thought it would go faster than that.

Can citric acid at the above mentioned ratios (1 TSP to 1 L/Q) ratio do damage to a brass boiler even with long term exposure? This chain argues the negative. The above posters have used citric acid for prolonged exposure: even weeks.

The reason I ask is that I've run across some how-to videos, such as those on Seattle Coffee's youTube site, which instructed against leaving citric acid in the boiler even overnight. It seems these videos are either overly cautious or maybe even misinformed. More experienced members seem to suggest that even three weeks would not prove excessive. Is this correct?

this is probably referring to the descaling of single-boiler (or dual boiler) machines by running citric acid solution through the boiler, heating it up and letting it soak.

the problem with that method of descaling is that it just works properly if if there's not too much scale build-up. (so only possibly as preventive descaling)

if you leave hot citric acid solution in the boiler overnight, it probably won't damage your brass boiler, but definitely wont go well on the seals. also, if there's is much scale build-up and high concentrations of citric acid are used precipitation of unsoluble calcium citrate might occur (especially on higher temperatures) which will then accumulate in the boiler (depends on boiler geometry, e.g. with silvia it won't be easily flushed out since theres a ascension pipe in the boiler)

in my opinion preventive descaling doesn't make much sense. better to use appropiate water and do a complete dissasembly and descaling when the machine shows symptoms of scale build-up. been running silvia for more than 2 years with water of ~5-6°dH (which would translate to 90-100 mg/ml CaCO3) and pH7 and there's still no sign of any mentionable scale build up....