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Inspector Banks


It is only a little over a week since I bottled my Mild Gravity homebrew, based on Graham Wheeler’s clone of Bank’s Hansons Mild but I’m trying it again. I haven’t tried it yet but it won’t be long. However, I was surprised at the high initial gravity I reached and, after leaving it in the fermentor a couple of weeks  I wondered if it had “cooked” too long. The earlier Slow Flowers brew I had made with the same approach (using my Codlo temperature controller) wasn’t as good as the brews I made the previous year and had also had a much higher than expected initial gravity. Time to investigate!

That is why I have christened this view Inspector Banks, in honour of Peter Robinson’s unorthodox but brilliant police inspector. We’ll have to wait to see if it turns out to be brilliant but I have to admit that I’m not carefully sticking to scientific method and only changing one variable at a time.

Firstly, I recently bought some mild ale malt so used this rather than the pale malt that was my base last time. Next, I needed to complete the initial cooking stage more quickly than last time so I used the oven to help control the temperature and mashed with a recipe scaled to 10l water rather than doing several smaller mashes in my slow cooker. I still used my Codlo to monitor the temperature but had to manually control the oven; this proved to be fairly straightforward – I had to keep an eye on it but it didn’t need that many adjustments.

I normally boil the wort for 90 minutes but, based on some recent reading, only gave it 60 minutes this time. An article from Brew Your Own magazine, for example, suggests that 90% of the hop utilisation will be done in this time. As normal, I then transferred to a heavy plastic jerry can and left overnight to cool. As before, my gravity was higher than expected (1.052 compared to a target of 1.035) but I think I have figured out the cause. Boiling reduces the relative amount of water in the mix at a consistent rate, based on atmospheric humidity and surface area. I started off with 10l water and probably had a little less than that after I’d removed the grain bag. By the time I’d boiled the wort for an hour, that had reduced to about 7l (so up to a 3l reduction in volume, although probably a bit less than that in practice). If I’d been brewing with 23l initial liquor, I’d still only have lost about the same if I’d had a pot of the same diameter but the proportionate loss would have been smaller (about a 13% loss compared to 30%) and that contributes to the original gravity reading along with the increased efficiency of having the grain freely floating in the full volume of the liquor.

In this case, I decided to add 2l water which reduced the OG to 1.039. Not only does this bring me closer to the target but it also means I get more beer for precious little extra investment in time or ingredients. If this brew turns out well, I can mark that as a extra value.

My final two innovations were in the fermentation stage. I’m using a dried yeast I haven’t tried before; Mangrove Jack’s Newcastle Dark Ale. I had thought about trying a couple of yeasts side by side with the same wort but, in the end, decided I didn’t have the time to set that up this time round. I also didn’t bother siphoning the wort from the jerry can to my fermentor. Instead, I put the rehydrated yeast in the bottom and poured the wort on top (although not down to the last dregs). The Irish Moss keeps the sediment fairly heavy so, although the fermenting liquid isn’t quite as clear as I normally have it, I don’t think that will hurt.

My last tweak isn’t something new. I’m going to start monitoring the gravity earlier and expect to bottle by next weekend rather than leaving for a fortnight. If I can get back to and build on the results I was getting last year, I’ll be very pleased and doubly so if some of the time saving changes turn out to help.

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