Making extract for later use or split brews

Hello from across the pond. I'm Duncan, and I'm a tad disorderly, when it comes to home brewing. New to all grain, only done a few kits previously, wondering if anyone makes an extract from a base malt, and then uses the extract to make a variety of small brews. I know quite a few people split a brew in two, but I'm thinking of making 3, 4, 5 or 6 low volume brews from a 5 gallon batch of home mashed extract. I would probably do this after the mash day, in the days ahead, storing the extract in a no chill stylee. This way I hope to try lots of different grains, hops and yeast more quickly than I other wise could. So I could add different steeped grains to different batches, as well as hops and yeast.

Any problems anyone can see with this, or any tips or experiences to share?

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First off, I have never tried this. Having said that, it sounds like an interesting idea... Except the no chill part. Barley is covered in wild yeast and bacteria. The boil sterilizes the wort. If you don't boil, these guys will start eating your wort and leaving nasty flavors behind that a later boil can't cure.

If you sterilize the wort first and store in a sterile container, this should work. Of course you will be boiling the wort twice, but the first time only needs to be 10 minutes or so ad you are not extracting hop acids.

If you do try this please post your results.

Thanks imrook. Yes, I omitted to mention that I would boil the wort before the no chill. If ten minutes is enough, that is good news. The main boil will come at a later date.

I guess I am going down the Aussie route, I will be doing BIAB brews with no chill and no hops ( I may use a neutral bittering hop to help guard against infection), then using the extract (possibly hopped) to make small batches of different beers using different specialty grains, hops and yeast, on future brew days.

I think the initial mash/boil day will be about 3 hours long. 40 mins prep ingredients and heat mash water, 90 minute mash (70 minute/20 minute sparge in second pot), 20 mins to bring to boil and boil, 15 minutes to cool a little and rack to no chill, 15 mins clean up. Guesswork. I will report back if anyone interested.

I then have additional extract style brewing sessions with small amounts, probably two at a time. Steep, boil, chill, pitch. Approx 2 hours. Probably 5 litre batches, but I may do a mix of sizes, some 5 litres, some 7.5 litres, some 10 litres. European spelling there...