It's a constant battle keeping prison inmates sober and drug-free.
An incident involving more than 20 drunken inmates at Hawke's Bay Prison on Monday revealed cell-brewed alcohol is an increasing problem.
Midland region manager Peter Grant said the brew had probably been made with "turbo-yeast" and water.
It could be brewed and consumed
within 24 hours, unlike the more conventional cell-brew which could take several days.
All it takes is a secure container, water and yeast.
The alcohol was often brewed in a plastic bag secreted in the bottom of an inmates' cardboard box of legal documents, for instance, or even in a compost heap.
"We are constantly amazed at their inventiveness."
The yeast is smuggled into the prison in small packets in any number of ways, but body cavities or the mouth were favourites.
Inmates working outside the jail can bring it in, as can visitors. Sometimes it can be thrown over the prison fence in an innocent-looking tennis ball to be picked up later.
Mr Grant said home brews were more dangerous than other drugs found in prisons, especially for inmates with alcohol problems who hadn't had any for several years.
"It can blow their heads off because they don't know how strong it is."
He said keeping drugs out of prison was a constant battle. Any level of drugs found in a prison was unacceptable and staff put a lot of effort into preventing it.
"We are finding home brews all over the place in the Midland region prisons, especially over the festive season.
Marijuana was the most common drug but "P" was making an appearance.
"We are concerned at the number of different ways they find to get it in to the jail."
Sometimes letter-writing paper is soaked in a P solution, dried, written on and posted to an inmate, who then soaked the paper in water to extract the P.
"Or they just eat the paper."
Inmates aren't allowed newspapers or magazines unless they are in sealed wrappers.
Any unwrapped magazines must be checked by staff before inmates are allowed them.
Drug dogs regularly check mail and intercept illicit drugs but staff and dogs can't check everywhere every day.
Sim cards for cellphones have been found hidden in the adhesive strip of envelopes.
Cellphones are smuggled in in parts and inmates can use their own Sim cards to make calls when they are reassembled. "It's a bit of a game for inmates to outwit staff."
