Cleaning RBFs

[indyspirits]

What are folks here using to clean their round bottom flasks? We're doing to some absinthe trials and, well, you know the story... My chemistry prof said lots of tarry shit is more soluble in elbow grease that in various solvents.   These boiling flasks are a serious PITA to clean.

 

 

[Silk City Distillers]

Coarse rock salt and ice cubes.  Shake the hell out of it.

That and shut down the distillation earlier than you might like.

[glisade]

I use PBW and bring it back up to near boil and let it soak for a bit. It's always taken everything out.

But I've also done something similar to Silk City but used rice and it works pretty good too.

[JustAndy]

I found using a stir bar on a magnetic stirrer/hot plate was a big help in preventing tarry residue. Also immediately dumping the flask after turning off the heat so it didn't dry onto the glass. 

[Silk City Distillers]

The ice and salt was a tip from one of my chemistry teachers as well.

Also, if your focused on flavor extraction from the boiling flask, you can hold back some of the spirit, and introduce additional spirit as you get towards the end of your extraction.  This technique works well when what you are extracting is very expensive, and when your solvent is cheap (ethanol).  The goal being, you finish the extraction before your solvent goes to tar.  In this case you trade off additional losses for less cleaning time.

You see this on some of the Rotovap units, they have an injection port to add additional solvent to the evaporation flask.

 

[indyspirits]

5 hours ago, Silk City Distillers said:

That and shut down the distillation earlier than you might like.

It's tough with absinthe as all of the louchey stuff is in the tails.   Buy yes, point well taken.

4 hours ago, glisade said:

I use PBW and bring it back up to near boil and let it soak for a bit. It's always taken everything out.

Will give this a try tmrw. Thanks!

1 hour ago, Silk City Distillers said:

Also, if your focused on flavor extraction from the boiling flask, you can hold back some of the spirit, and introduce additional spirit as you get towards the end of your extraction

By spirit you mean GNS?