Dry hopping w Grainfather GF30 conical fermenter

[samosbrew]

Hi there - first time poster!

I'm trying to figure out the best way of dry hopping in a Grainfather GF30 conical fermenter (with dual valve tap) while minimising oxygen exposure. So far I've just opened the fermenter and lobbed hops in a few days before fermentation ends, which has worked fine enough for the styles I'm brewing. However, I plan to abandon this method because I'd like to dry hop after fermentation has finished, and want to brew some beers that are more prone to oxidation, so can't rely on fermentation using up any oxygen that enters from opening the lid.

The Grainfather website suggests using the pressure transfer kit to add 1 PSI of CO2 to the fermenter to create positive pressure with CO2 and so minimise oxygen exposure when you open the lid (link here). I'm confused about the detail: the Grainfather website suggests bubbling CO2 up through the beer from the sample outlet of the dual valve at the bottom of the fermenter; but, as far as I'm aware, the pressure transfer kit attaches to the top of the fermenter. I also don't understand the benefit of adding CO2 pressure from the bottom, when it can just be added via the top of the fermenter.

Does anyone have experience of this method who could lend a hand? Otherwise, do you have any other tips for dry hopping with this fermenter?

 

[Agentgonzo]

I think the idea of adding CO2 from the bottom is that it creates a net flow of CO2 upwards through the fermenter, then out of the airlock.

If you then add hops from the top, they fall downwards (gravity) but any oxygen they "drag" along with them gets pushed out via the upwards flow of CO2 and out of the fermenter.

If you were to push co2 in from the top, then when you add hops from the top, the oxygen they "drag" in doesn't get pushed out via the CO2 upwards flow and can stick around in the fermenter and spoil your beer

 

[Stu's Brews]

The Grainfather website suggests using the pressure transfer kit to add 1 PSI of CO2 to the fermenter to create positive pressure with CO2 and so minimise oxygen exposure when you open the lid (link here). I'm confused about the detail: the Grainfather website suggests bubbling CO2 up through the beer from the sample outlet of the dual valve at the bottom of the fermenter; but, as far as I'm aware, the pressure transfer kit attaches to the top of the fermenter. I also don't understand the benefit of adding CO2 pressure from the bottom, when it can just be added via the top of the fermenter.

This is what I do and it works fine.

The reason it states you need the pressure transfer kit is because the tri-clamp fitting has a pressure relief valve. It's for safety to stop you over-pressuring the fermenter.

For getting CO2 into the fermenter you simply need to connect a gas line to the inlet valve. Set the pressure to 1-2psi and then open the valve.

 

[samosbrew]

Thanks very much; both really helpful replies! (Particularly for someone whose not pressured transferred before or has any experience using CO2)

@Stu's Brews - do you have any advice on how best to connect a gas line to the inlet valve? I think I could screw a john guest fitting onto the inlet valve and attach a gas line (push fit), but I'm not sure if the push fit is secure enough with the 1-2 psi of pressure to bubble CO2 up. What do you do?

 

[tigertim]

You can use one of these to connect 3/8ths beer/gas line to the bottom of the grainfather dual-valve in order to push CO2 in or draw beer out. This is how I transfer oxygen-free to keg; directly from the bottom of the fermenter to the liquid post on the keg.

https://www.themaltmiller.co.uk/product/john-guest-3-8-push-fit-to-3-8-bsp-adapter-pi011213s/

You can also get a 90 degree elbow to prevent putting pressure on the valve with the abrupt bend on the pipe

John Guest 3/8″ Push Fit to 3/8″ Stem Elbow - The Malt Miller

I tend to be lazy and leave the lid in place and pour the hops through the airlock hole, but I don't tend to brew many massively oxygen-sensitive beers so I generally get away with it

 

[tigertim]

Also, something worth mentioning which I often see glossed over is purging air from CO2/beer lines.

As a refrigeration engineer, when connecting any kind of hoses, manifold, equipment or refrigerant to refrigeration equipment, it's essential to flow refrigerant through the hoses and manifold to purge the air before opening them to the system. Allowing air, moisture or other non-condensibles into a refrigeration system causes big problems.

Likewise, I've seen a few tutorials for oxygen-free beer transfer where a length of pipe is connected between the CO2 and the bottom of the fermenter, the taps are then just opened and the whole column of air from the pipe is bubbled up through the beer before the CO2 from the cylinder comes through. Easily done, but catastrophic if your beer is massively oxygen-sensitive.

 

[hoppyscotty]

Also, something worth mentioning which I often see glossed over is purging air from CO2/beer lines.

As a refrigeration engineer, when connecting any kind of hoses, manifold, equipment or refrigerant to refrigeration equipment, it's essential to flow refrigerant through the hoses and manifold to purge the air before opening them to the system. Allowing air, moisture or other non-condensibles into a refrigeration system causes big problems.

Likewise, I've seen a few tutorials for oxygen-free beer transfer where a length of pipe is connected between the CO2 and the bottom of the fermenter, the taps are then just opened and the whole column of air from the pipe is bubbled up through the beer before the CO2 from the cylinder comes through. Easily done, but catastrophic if your beer is massively oxygen-sensitive.

This is very important. I once replaced a co2 line to a keg and forgot to purge it before reconnecting and my beer was oxidised within a few days.

One option for dry hopping is to add about 0.3G per 20litres of sodium metabisilphate with your dry hops. This will scrub dissolved oxygen in the beer and the air. It’s very effective if you can’t guarantee oxygen ingress. Some people think it impacts the flavour of the beer but you can dose it lower than what I suggest above which is towards the higher end of dosing.

 

[Caramel Ox]

The fermenter has a 2” triclamp on the top as I understand, which would enable you to use a hop bong to drop purged hops in.

 

[Stu's Brews]

Thanks very much; both really helpful replies! (Particularly for someone whose not pressured transferred before or has any experience using CO2)

@Stu's Brews - do you have any advice on how best to connect a gas line to the inlet valve? I think I could screw a john guest fitting onto the inlet valve and attach a gas line (push fit), but I'm not sure if the push fit is secure enough with the 1-2 psi of pressure to bubble CO2 up. What do you do?

I essentially use this:

https://www.themaltmiller.co.uk/product/pressure-transfer-and-low-o2-dry-hop-kit-v1/?v=79cba1185463
3/8" gas line connected to some 12mm silicon tubing, using a 1/2″ to 3/8″ JG fitting.

 

[CookieMonster]

The fermenter has a 2” triclamp on the top as I understand, which would enable you to use a hop bong to drop purged hops in.

The grainfather fermenter has a 1.5" triclamp. Although you're right, I've used the hop bong for some time and never had issues with oxidation...although it can be a bit of a pain sometimes getting the hops to drop through, a bit of a shake and wiggle usually does the trick. They're out of stock from BKT at the minute, but it's the butterfly valves that are out, you can still get all the ancillary pieces from them and get the valves separately. Here's a website selling the valves VEVOR VEVOR Sanitary Butterfly Valve 2 Pack Stainless Butterfly Valve 1.5" Tube Outer Diameter Triclamp Butterfly Valve 304 Stainless Steel Sample Valve Tri Clamp with Pull Handle for Controlling the Fluid | VEVOR UK
Works out cheaper than getting the kit and you get 2 valves!

 

[samosbrew]

Thanks everyone for your input. Much appreciated!

@tigertim - thanks for directing me too the parts! And good reminder about air in the gas line. I'll keep that in mind.

@Caramel Ox, @CookieMomster - I'll consider a hop bong, but for now I want to see if I can do it without. I want to get equipment to pressure transfer out of the fermenter, so if I can also dry hop with the pressure transfer kit I'd rather skip buying a bong as well for now. Good to have in mind as an alternative, though!

@Stu's Brews - thanks for directing me to that!

 

[Caramel Ox]

I’ve considered drilling the flat lid of my fermenter to take a triclamp fitting. Since the butterfly valve goes on first you can switch other fittings when needed. Also without any practical experience of it - it seems like a sight glass would do an equivalent job.

 

[CookieMonster]

Thanks everyone for your input. Much appreciated!

@tigertim - thanks for directing me too the parts! And good reminder about air in the gas line. I'll keep that in mind.

@Caramel Ox, @CookieMomster - I'll consider a hop bong, but for now I want to see if I can do it without. I want to get equipment to pressure transfer out of the fermenter, so if I can also dry hop with the pressure transfer kit I'd rather skip buying a bong as well for now. Good to have in mind as an alternative, though!

@Stu's Brews - thanks for directing me to that!

No worries, assuming your transferring into corny kegs, I've found this kit perfect! (https://www.themaltmiller.co.uk/pro...-transfer-and-blow-off-system/?v=79cba1185463) Does the job very well, never had any problems with it and it's cheaper than the OEM one

 

[Garry247]

if anyone has a spare valve to sell rather then me buy two that would be great

 

[JockyBrewer]

Hi @samosbrew

I've brewed some absolutely mega hoppy beers, including NEIPAs and TIPAs that have 500g of hops for a 19 litre beer, a large chunk of which go in after fermentation, so I've been very picky about oxygen ingress. I also have a Grainfather GF30.

When dry hopping I've not found anything with benefit more than just popping out the bung/triclamp on the top and dump the hops in quickly. The headspace at that point is nearly 100% CO2, so you're really not letting much oxygen in.

If you do wish to push CO2 into your fermenter (and I do push CO2 up the dump valve sometimes to rouse hops), purging hoses before pushing CO2 into the fermenter is very important as you could end up pushing oxygen in to your beer - way more than you would by just dumping in hops without pushing CO2.

More important with hoppy beers is the careful handling into keg. Fully purge your receiving keg before kegging - fill it with starsan and then push it out with CO2. A pressure transfer kit is very useful for racking to keg because the fermenter racking port is a bit small and so very slow to transfer via gravity alone. If you get the official Grainfather pressure transfer kit then the racking cane is a great backup for when the bottom racking port gets clogged.

 

[Tess Tickle's Brewery]

Just noticed this great price on these from B2B. There are 11 in stock according to the website. £50 cheaper than TMM.

https://brew2bottle.co.uk/products/grainfather-conical-fermenter-pro-edition

 

[JockyBrewer]

Just noticed this great price on these from B2B. There are 11 in stock according to the website. £50 cheaper than TMM.

https://brew2bottle.co.uk/products/grainfather-conical-fermenter-pro-edition

Until they replace the stupid bottom valve I wouldn’t recommend this fermenter, and I’ve had two in two separate periods.

I love the cooling jacket and integrated heating and temperature control (I have the GC2 glycol chiller), but:
1. The racking port is easily blocked
2. The legs aren’t long enough and get in the way
3. The dump valve isn’t particularly sanitary if you want to crop yeast

Brewbuilder conical or SS Brewtech is what I’d recommend.

 

[Tess Tickle's Brewery]

Until they replace the stupid bottom valve I wouldn’t recommend this fermenter, and I’ve had two in two separate periods.

I love the cooling jacket and integrated heating and temperature control (I have the GC2 glycol chiller), but:
1. The racking port is easily blocked
2. The legs aren’t long enough and get in the way
3. The dump valve isn’t particularly sanitary if you want to crop yeast

Brewbuilder conical or SS Brewtech is what I’d recommend.

Get where you're coming from with those points but:-

1. I'm hoping regular yeast dumps will stop that from happening (only done one brew so far). They recommend dumping every 3 days or so.
2. I agree on the legs point so I have bought a piece of tubing to direct the trub into the waste container. Also bought the malt miller pressure transfer kit which makes pressure transfers from the bottom a lot easier, with the help of the john guest fittings they provide.
3. Not a problem for me as I don't ever save yeast.

All things to consider for potential buyers.

 

[JockyBrewer]

Get where you're coming from with those points but:-

1. I'm hoping regular yeast dumps will stop that from happening (only done one brew so far). They recommend dumping every 3 days or so.
2. I agree on the legs point so I have bought a piece of tubing to direct the trub into the waste container. Also bought the malt miller pressure transfer kit which makes pressure transfers from the bottom a lot easier, with the help of the john guest fittings they provide.
3. Not a problem for me as I don't ever save yeast.

All things to consider for potential buyers.

All good points. I bought some 16mm internal diameter silicone tubing that fits over the dump port (with a bit of starsan to help ease it on), and that works well. I've also found that blowing some CO2 up there then coming back next day to dump yeast means it flows nicely, particularly if you've also dry hopped. Putting it on a table has also made it infinitely easier to use.

I'm still learning to 'drive' the conical, but it feels harder than it should be. If they brought out a new version with a 1/2" rotating racking valve/arm I'd buy it tomorrow.

 

[Tess Tickle's Brewery]

I've put mine on a stool for the time being, but it means I need help from the hubby to lift it onto it when full. (and stepladders as I'm 5ft 3)

By the way the ice box works incredibly well. I couldn't afford the glycol chiller as yet but might not bother at all now. Stayed at 10c perfectly with two 2L bottles of ice, changed morning and night.