PG#1 - Parti-Gyle Porter & Mild (with photos)

[stitch]

Hi

I completed my first parti-gyle brewday at the weekend. Here's how I thought it would go: viewtopic.php?f=5&t=53276

First off, I didn't actually have as much flaked barley as I wanted, but no matter: I chucked all I had in anyway.

Grist summary:

• 5.64kg Pale Malt
  290g Flaked Barley
  600g Amber Malt
  375g Chocolate Malt
  300g Medium Crystal

The idea was to split the wort into two 17.5 litre batches. The first batch being a strong beer (porter) at 1.054 and the second batch would be weaker (mild) at 1.039. I found some calculations somewhere on the net that suggested I'd get about 58% of the strength (litre-degrees) in the first batch and 42% in the second. So on this basis I built a spreadsheet for calculating what sort of grain bill & liquor volumes I'd need for the gravities I desired. Here's a photo (look at the two lines marked "2 Batch", the yellow fields are user-editable):


Here's how it actually went:

So I woke up bright and early on Sunday morning. Brewday started about 6.45am:


Here's me painstakingly measuring out 7.5kg of grain kilo by kilo on my inherited 70s kitchen scales. What do other people use?


Grain shot:


I was aiming for 67C for the mash, but it came out at 66. Who am I to argue:


Lost 1.5 degrees over 90 minutes:


First runnings:


The first 17.5 litres actually came out at 1.073:


Here's the second batch:


The second batch came out at 1.031 (actually 20 litres at 1.027 cos I cocked up, but if it was boiled down to 17.5 litres it would be 1.031).

So the 58%/42% ratio I found on the net didn't work for me. It was actually 79% of the strength (litre-degrees) was in the first half and 21% in the second. Which is fine, in the future I know what to expect and can adjust accordingly.

So, I just ended up jugging 7 litres from the "porter" to the "mild" to bring it up to strength. Then I jugged 7 litres back to the porter so I still had two equal-sized batches (except the mild was 2.5 litres bigger, cos I cocked up, but let's not get into details.)

I ended up with:

• 17.5 litres of 1.057 "porter"
  17.5 litres of 1.039 "mild" (actually 20L of 1.034)

which is pretty close to what I was hoping to achieve and I'm happy about that. I can't be bothered to work out the precise efficiency, but it was a bit more than the 72% I estimated.

Moving on, chicken & grain shot:


The mild boiling with its meagre 15 IBUs of Fuggles:


Pitching a jar of rinsed Wyeast 1968 yeast into the mild:


Porter hot break:


I changed the hop schedule for the porter, cos I didn't like it. Ended up as Magnum & Northdown bittering to about 27IBU, then about 28g Northdown at 10 minutes from the end (10 IBUs) and a further 28g of Fuggles at flame-out. Is it a bit hoppy? Maybe. Hops (& Irish Moss):


Chilling:

Don't worry all the electrics are off.

Pitching the stepped up fridge yeast:


Phew. It was a long day. From around 6.45am to 4.30pm. But I got two brews out of it, while only doing one mash, so I think it was pretty successful. Hopefully with the different alcohol strengths and hopping schedules the two beers won't be too samey. We'll find out and if they are I'll just have to brew something else too. Perhaps a Bitter/IPA parti-gyle...

Cheerio!

[fego]

Nice one and nice idea. I might give that a go one day using both of my boilers at the same time.

On weighing grain, I use a digital set of scales and put a large jug on it before turning it on (thus ignoring the jug's tare). As it happens, the jug I use contains exactly 1kg of pale Malt when full so i just bung say 4 jugs full in a container and know I've got 4 kilos in there. I then top up as the recipe requires. Other grains have a different weight to volume ratio so I weigh them out separately.

[stitch]

Yeah - two boilers would massively reduce the length of the day. And I guess sort of the point of this was because my single boiler isn't big enough to boil all the wort I can get out of my mash tun: so do it in two stages and see what comes out.

Makes sense using the volume of pale malt to work out its weight. That's probably a lot easier than weighing it out. I've got a small set of digital scales I use for hops, but they max out at 350g so I should probably buy a decent set of kitchen scales for the additional grains. My Gran's scales are still accurate though, despite being nearly 40 years old. They don't make em like they used to!

[Wolfy]

Love the yeast rinsing.
It looks like you cool your wort to pitching temperature before it is transfered to the FV. What I like to do in this case is drain some of the fresh-cool-wort into the starter/washed yeast container, and shake it all up (while the rest of the fermentor is filling) this means you can easily rinse all the yeast out, and that portion of wort the yeast 'wakes up in' will be well oxygenated (at least for the 15 mins or so it takes for you to fill the FV).

[stitch]

Oh yeah. Obvious now - it did sort of gloop out. There's so many tiny tricks to this brewing lark

Both sets of yeast were well over-pitched anyway. In fact fermentation is done and I've transferred the mild into a barrel and I'm about to put the porter in secondary for another week or so.

[Wolfy]

Over pitching (or rather simply pitching a large amount of healthy viable yeast) is a good way of getting a good, clean, fast ferment (great for most American-style beers), however sometimes when you want a yeast-driven beer (UK mild/ale), it can be useful stress the yeast some, and one way to do that is by limiting the pitching rate. It all depends on what you're trying to do.

[stitch]

I over-pitched mainly because I didn't actually know how much yeast I had.

I bought a packet of wyeast 1968 a couple of months ago and immediately stepped it up to about 600 bil yeast cells (according to http://www.yeastcalc.com). Chucked half in a brew and split the other half amongst a bunch of plastic slant-type tubes and put them in the fridge. They fermented everywhere and burst out the tops but I still had a load left. I just didn't have much of an idea how much. So I stepped them up twice again for this porter.

The rinsed yeast came out of a brew I made a couple of weeks ago and has been sitting in the fridge since.

Is there a rule of thumb for estimating the number of cells per ml of yeast-gloop?

[barney]

Looks like you had good fun, were you surprised how seamlessly it all seems to flow?

The next time will be a lot easier.

You have got me thinking of another parti-gyle now.

[Wolfy]

The rinsed yeast came out of a brew I made a couple of weeks ago and has been sitting in the fridge since.

Is there a rule of thumb for estimating the number of cells per ml of yeast-gloop?

The MrMalty calculator has a 'slider' that can be adjusted based on how thick the slurry is (and other stuff).
There are some more details on Braukaiser if you want to get more technical.

I work on the (simplified) assumption that 40mls of my clean-washed-settled-slurry has about 100billion cells.
However, in theory, you should get the most accurate slurry-cell-count estimate by using weight and not volume (I've not bothered to weigh my yeast-containers yet, but should someday).

[stitch]

Looks like you had good fun, were you surprised how seamlessly it all seems to flow?

Yeah - it was great. At the end of the day it's just a big mash where you separate the batches. When the batches come out at different gravities you can then mix them to get whatever different gravities you desire. Trick is to not freak out.

The next time will be a lot easier.

Just like all processes - the first few all-grain brews I did, I had to have a long list of all the steps I needed to take. Now it flows well and I know what I'm doing, I'm sure parti-gyles will soon become another method available to me.

The MrMalty calculator has a 'slider' that can be adjusted based on how thick the slurry is

Ah, I forgot about Mr Malty - I've used http://www.yeastcalc.com more as it shows how to step up a smaller amount of yeast. But MrMalty's slurry tool looks dead useful.

[Laripu]

I like the idea, and the pics were great.

BTW, we have the same robe, but mine is dark green. I often wear it if it's an early brew day too.

[Goulders]

Great brewday thread!

I didn't quite get how you worked out to jug 7 litres from the porter to the mild to bring up to strength. I guess that is ratios etc, but did you read up somewhere to help you out with the calculations? I found this website link with a spreadsheet, but too late at night to get my head around this! And did you batch sparge?

I currently BIAB, but hoping to get a big mash tun with a view to a ESB/London Pride parti-gyle at some point.

Cheers

[stitch]

Great brewday thread!

Thanks! It was a great brewday, if a bit long. Next time will be shorter.

I didn't quite get how you worked out to jug 7 litres from the porter to the mild to bring up to strength.

I didn't work it out, I just kept jugging it over and checking the gravity of the mild each time. I didn't try and work it out because I figured I had the two batches in front of me and didn't really need to.

did you read up somewhere to help you out with the calculations?

Yeah, I used this article by Randy Mosher. But found his ratios (58%/42%) didn't work for me. Next time I'll try the Batch Sparge and Party Gyle Simulator spreadsheet on the Braukaiser site. Putting my numbers in to that, the values I got out looked more like my actuals. The spreadsheet looks quite complicated though.

I found this website link with a spreadsheet

Cheers, I'll check that out.

And did you batch sparge?

Yep. Two batches, "porter" & "mild".

I currently BIAB, but hoping to get a big mash tun with a view to a ESB/London Pride parti-gyle at some point.

Sounds good. I've a feeling it might make more sense for more similar styles, like two bitters, or IPA & bitter, or stout & forrin xtra stout/imperial stout.

I've got the mild conditioned in the barrel at the moment and it's pretty good. The porter, in bottles, tastes less pleasant. But I'm hoping it just needs a bit more time for the hoppy bitterness to mellow out.

Cheers!

[Capn Ahab]

Looks great!

Feel like sharing? Bring em down the miners arms in st Werburghs on the third Thursday of the month and meet some other brizzle brewers

[Goulders]

Cheers Stitch, great info there. I did a porter and found it tasted better after a few months conditioning. Should be good for the winter, as not in a porter mood in the warmer weather!