A few (probably simple) questions

[GMH]

Have just done a first extract brew based loosely on OSB’s extremely helpful recipe/technique for a 10L batch. Despite this possible success (still fermenting), I have a few questions that I can’t find answers to:

1) Having acquired a nice 17L pot I was thinking of doing a small volume brew like OSB’s ‘all in’ – given that I have the capacity for a full boil of a smaller brew length can I simply half the quantities of a 23L recipe and make it up to 11.5L (or thereabouts)?

2) Assuming the above would be similar to a full 23L batch involving all the malt/sugar throughout the hop schedule, my obvious question is…do I make up for any evaporation/hop absorption at the end of the boil or attempt to compensate by boiling down to a target volume?

3) When using various additions of hops recipes seem to list a time in minutes – is there a standard total boil time (an hour for example) with these times equating to the period they are in the wort (i.e. 15mins going in at 45mins of the 60min boil)? Or is it based on the first addition with these intervals tacked on (i.e. first in for 45mins and the second for 15mins making a boil time of 60mins)?

4) And finally…scaling up! Is there a simple way of condensing a full boil extract recipe so that it can be done as a partial boil in the above mentioned pot? I assume this would mostly involve adjusting for the hop utilisation and over-bittering, but my maths isn’t up to much…

Many thanks for any replies!

Dave.

[Waffty]

1) As a general rule, yes it should be a simple case of halving the quantities but there are still constants, such as obsobtion etc, which you're best to test out with software, such as BeerSmith or BeerEngine.

2) You will get evaporation but this isn't an issue, as you can always top up your fermenter with boiled/cooled water after you've finished the main boil i.e on my 19L pot on a 60min boil I require 5L of top up. This I boil/cool on a smaller pan, before toping up.
As for topping up later, yes, you will need 'more' hops, extract etc, as they will both be diluted out, when you make up the volume i.e in my example above, my OG out of the main boil is 1.050 & ends up at 1.040'ish after being diluted. Again, BeerSmith can help with this.

3) There are two main schools of thought with the boil, so say 60 minutes, so say 90 minutes (& some say 120 minutes). If you boil for 90 mins, you get a better hop utilisation, so can use less (in terms of quantity). I use 60 minute boils & take the hit on the hop quantites + it keeps the wife happy.

4) You can make a small batch & dilute up but your hop utilisation will trail off considerably i.e in a 1.020 wort, you'll get possible twice the utilisation, against a 1.050 wort. Again, BeerSmith can help with these calculations.

[OldSpeckledBadger]

1) Yes

2) Ideally you pre-boil volume would be just large enough to give you the target volume after loss to evaporation and hops. This is not easy to calculate though. What I suggest you do is bring to a good rolling boil an exact voume of water (say 10 litres) in your pot for an exact time (say 30 minutes) then let it cool and measure how much water is left. This will show you what your evaporation losses are and will allow you to calculate how much extra liquid you'll need at start of boil. You can make up the losses to hops at the end.

3) The standard boil time, if there is such a thing, is 90 minutes but there are plenty of skilled brewers on this forum who get good results with shorter boil times. Hop addition times are always referenced from the end of the boil so if you see a hop schedule which says x grammes of Challenger at 90 minutes and y grammes of Goldings at 10 minutes it means the Challenger goes in at the start and the Goldings 10 minutes from the end.

4) As long as you've got a nice piece of software such as Beer Engine it's quite simple. Say you want to make 23L but don't have the boiler capacity. Let's keep it simple and have a target boil volume of 11.5L. Let's also say that the beer is supposed to have a bitterness of 30EBU. We need to end up with 11.5L with a bitterness of 60EBU. So it's just a matter of playing around in Beer Engine adjusting the amount of malt extract in the boil until we get 60EBU.

[GMH]

Thank your very much for your time gentlemen – I really appreciate the help! Time to start playing with Beer Engine me thinks…

[Waffty]

I use BeerSmith, it does cost £20 to register (you can use it free for a month, fully functional) but if you take the time to set it up correctly, you'll be able to do everything you want too, as it will give you very acturate top up figures i.e my brew length schedule advises 5.5L, so I boil up 6L & have 'change'.

It's also good for working out reduced brewlengths plus it's good for hop utilisation, against a specific OG. There's a good conversion utility from all grain brews to extract & advises if some of the ingrediants can't be used in an extract only brew (torified wheat etc). The software, also gives you a brewing schedule, which helps you to plan your day i.e give a running order, temps, top up values etc. There's a list of all the yeasts (from all the major suppliers), which gives their attenuation & gives reasonably good projected final gravities.

I've used it exclusively for 12 months now & can't speak any more highly.

Deffo worth a try, as it won't cost you anything for 30 days.

Darren.